By Authority Of THE UNITED STATES OF AMERICA Legally Binding Document

Transcription

1 By Authrity Of THE UNITED STATES OF AMERICA Legally Binding Dcument By the Authrity Vested By Part 5 f the United States Cde 552(a) and Part 1 f the Cde f Regulatins 51 the attached dcument has been duly INCORPORATED BY REFERENCE and shall be cnsidered legally binding upn all citizens and residents f the United States f America. HEED THIS NOTICE: Criminal penalties may apply fr nncmpliance. e Dcument Name: UL 1042: Electric Basebard Heating Equipment CFR Sectin(s): 24 CFR Standards Bdy: Underwriters Labratries Official Incrpratr: THE EXECUTIVE DIRECTOR OFFICE OF THE FEDERAL REGISTER WASHINGTON, D.C.

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3 ANSI UL 1042 ;tandard fr Safet - Electric Basebard Heating Equipment UL 1042 ISBN

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5 Nvember 2, 1995 Revisin pages fr Standard fr Electric Basebard Heating Equipment UL 1042, Furth Editin Attached t this transmittal ntice is a reprinted title page fr the Furth editin f UL Attentin is directed t the nte n the title page f this standard utlining the prcedure t be fllwed t retain the apprved text f ANSIjUL Attentin is directed t the nte n the title page f this standard utlining the prcedure t be fllwed t retain the Department f Defense apprved text f UL Revised and/r additinal pages may be issued frm time t time. With the inclusin f the accmpanying material, the standard cnsists f pages dated as shwn in the fllwing checklist: Page Date (J 1... April 11, 1994 (Reprinted Nvember 2, 1995) April 11, June 7, , April 11, June 7, ' April 11, , June 7, , A1..., April 11, 1994

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7 l {'... American Natinal Standard APRIL 11, 1994 ~ ANSI/UL (Title Page Reprinted: Nvember 2, 1995) 1 UL 1042 Standard fr Electric Basebard Heating Equipment Prir t the first editin, the requirements fr the prducts cvered by this standard were included in the Standard fr Electric Space Heating Equipment, UL 573. First Editin - June, 1972 Secnd Editin - March, 1979 Third Editin - September, 1987 Furth EdHin April 11, 1994 Apprval as an American Natinal Standard (ANSI) cvers the numbered paragraphs n pages dated April 11, These pages shuld nt be discarded when revised r additinal pages are issued if it is desired t retain the ANSI apprved text. An effective date included as a nte immediately fllwing certain requirements is ne established by Underwriters Labratries Inc. Apprved as ANSljUL , September, 1986 Apprved as ANSI jul , September 11, 1995 The Department f Defense (000) has adpted UL 1042 n August'30, The publicatin f revised pages r a new editin f this Standard will nt invalidate the 000 adptin. Revisins f this standard will be made by issuing revised r additinal pages bearing their date f issue. A UL Standard is current nly if it incrprates the mst recently adpted revisins, all f which are itemized n the transmittal ntice that accmpanies the latest published set f revisin pages. ISBN COPYRIGHT 1987, 1995 UNDERWRITERS LABORATORIES INC.

8 2 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11,1994 CONTENTS FOREWORD 1 Scpe Units f Measurement Cmpnents... 6 CONSTRUCTION 4 Frame and Enclsure Accessibility f Uninsulated Live Parts, Film-Cated Wire, and Mving Parts Parts Subject t Pressure Assembly Air-Handling Cmpartments Prtectin Against Crrsin Permanently Cnnected Equipment Crd-Cnnected Heaters Current-Carrying Parts Internal Wiring Heating Elements Electrical Insulatin Thermal Insulatin... : Mtrs Mtr Overlad Prtectin Overcurrent Prtectin Thermal Cutffs Receptacles and Transfer Switches Lamphlders Switches Autmatic Cntrls and Cntrl Circuits... ' Spacings Grunding Guarding f Heating Elements Flr Heaters PERFORMANCE 29 General Pwer Input Test... ' Leakage Current Test Cntinuity f Grunding Cnnectin Test Temperature Test Abnrmal Operatin Test... ; Overvltage Test Mtr Switch Overlad Stability Test Tip Over Test Cheeseclth Drape Test Stalled Fan Test Padded Surface and Blanketing Test Curtain Drape Test... 53

9 (:J "''"!i ':;?8r,tr:~'i; C"l~:';' ;, '. -,- ' < ~ April 11, 1994 Standard fr Electric Basebard Heating Equipment UL 1042, Furth Editin Accmpanying this transmittal ntice is a cpy f the furth editin f UL THIS EDITION OF THE STANDARD IS NOW IN EFFECT. Revised and/r additinal pages may be issued frm time t time. Subscribers t UL's services in the area cvered by this standard will receive these revised and/r additinal pages autmatically. Others may receive such pages by subscribing t UL's subscriptin service fr revisins. See UL's CATALOG OF STANDARDS FOR SAFETY fr a descriptin f the revisin subscriptin service, the cst f the service fr this standard, and rdering infrmatin.

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11 APRIL 11, UL 1042 Standard fr Electric Basebard Heating Equipment First Editin - June, 1972 Secnd Editin - March, 1979 Third Editin- September Prir t the First Editin the requirements cvered by this standard were included in the Standard fr Electric Space Heating Equipment, UL 573. Furth Editin April 11, 1994 Revisins f this standard will be made by issuing revised r additinal pages bearing their date f issue. A UL Standard is current nly if it incrprates the mst recently adpted revisins, all f which are itemized n the transmittal ntice that accmpanies the latest published set f revisin pages. ISBN COPYRIGHT UNDERWRITERS LABORATORIES INC.

12 2 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11,1994 CONTENTS FOREWORD 1 Scpe Units f Measurement Cmpnents... 6 CONSTRUCTION 4 Frame and Enclsure Accessibility f Uninsulated Live Parts, Film-Cated Wire, and Mving Parts Parts Subject t Pressure Assembly Air-Handling Cmpartments Prtectin Against Crrsin Permanently Cnnected Equipment Crd-Cnnected Heaters Current-Carrying Parts Internal Wiring Heating Elements Electrical Insulatin Thermal Insulatin Mtrs Mtr Overlad Prtectin Overcurrent Prtectin Thermal Cutffs Receptacles and Transfer Switches Lamphlders Switches Autmatic Cntrls and Cntrl Circuits Spacings Grunding Guarding f Heating Elements Flr Heaters PERFORMANCE 29 General Pwer Input Test Leakage Current Test Cntinuity f Grunding Cnnectin Test Temperature Test Abnrmal Operatin Test Overvltage Test Mtr Switch Overlad Stability Test Tip Over Test Cheeseclth Drape Test Stalled Fan Test Padded Surface and Blanketing Test Curtain Drape Test... 53

13 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL ':!J () 43 Shredded Paper Test Hydr-Static Pressure Test Static Lad Test Water Splash Test Impact Test Strain Relief Test Burnut Test (Slid-State Cmpnents) Dielectric Vltage Withstand Test Humidity Cnditining Test Marking Plate Adhesin Tests MANUFACTURING AND PRODUCTION TESTS 53 General MARKING AND INSTRUCTIONS 54 Marking... ;' Instructins APPENDIX A Standards fr Cmpnents..., A 1 I

14 4 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, 1994 FOREWORD A. This Standard cntains basic requirements fr prducts cvered by Underwriters Labratries Inc. (UL) under its Fllw-Up Service fr this categry within the limitatins given belw and in the Scpe sectin f this Standard. These requirements are based upn sund engineering principles, research, recrds f tests and field experience, and an appreciatin f the prblems f manufacture, installatin, and use derived frm cnsultatin with and infrmatin btained frm manufacturers, users, inspectin authrities, and thers having specialized experience. They are subject t revisin as further experience and investigatin may shw is necessary r desirable. B. The bservance f the requirements f this Standard by a manufacturer is ne f the cnditins f the cntinued cverage f the manufacturer's prduct. c. A prduct which cmplies with the text f this Standard will nt necessarily be judged t cmply with the Standard if, when examined and tested, it is fund t have ther features whiph impair the level f safety cntemplated by these requirements. D. A prduct emplying materials r having frms f cnstructin differing frm thse detailed in the requirements f this Standard may be examined and tested accrding t the intent f the requirements and, if fund t be substantially equivalent, may be judged t cmply with the Standard. E. UL, in perfrming its functins in accrdance with its bjectives, des nt assume r undertake t discharge any respnsibility f the manufacturer r any ther party. The pinins and findings f UL represent its prfessinal judgment given with due cnsideratin t the necessary limitatins f practical peratin and state f the art at the time the Standard is prcessed. UL shall nt be respnsible t anyne fr the use f r reliance upn this Standard by anyne. UL shall nt incur any bligatin r liability fr damages, including cnsequential damages, arising ut f r in cnnectin with the use, interpretatin f, r reliance upn this Standard. F. Many tests required by the Standards f UL are inherently hazardus and adequate safeguards fr persnnel and prperty shall be emplyed in cnducting such tests.

15 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL INTRODUCTION 1 Scpe 1.1 These requirements cver prtable and fixed electric basebard heating equipment rated at 600 vlts r less, t be emplyed in rdinary lcatins in accrdance with the Natinal Electrical Cde, ANSI/NFPA Basebard heating equipment includes basebard heaters and basebard heater accessries. 1.3 Electric basebard heating equipment intended fr use in a hazardus lcatin is judged n the basis f cmpliance with the requirements in this standard, tgether with thse recgnized requirements applicable t usage in hazardus lcatins. 1.4 Any air heating appliance sld r recmmended fr use as a basebard heater, irrespective f its dimensins r ther characteristics, is t be identified as a basebard heater. It will be categrized as a fixed r prtable basebard heater in accrdance with the fllwing: a) Fixed - A heater is identified as a fixed basebard heater if: 1) The heater is less than 6 inches (150 mm) in verall depth, the rati f the verall length t the verall height is mre than tw t ne, and the heater can be installed cmpletely within a space f 18 inches (460 mm) abve the flr; r 2) The heater enclsure is intended t be cnnected t ther heater enclsures t frm a system. Exceptin: A heater intended fr ceiling munting r suspended munting r marked -D Nt Install Less Than 6 Feet Frm Flr- is nt cnsidered t be a basebard heater even if it meets the specificatins in (1) r (2) abve. b) Prtable - A prtable heater is identified as a basebard heater if, excluding prjectins f guard r feet, it is less than 5 inches (130 mm) in depth and if the rati f its verall length t its height withut the handle is as fllws: Maximum height f heater, feet (mm) Rati f length t height 2 (610) Mre than 2 t 1 Over 2 (610) Mre than 3 t 1 Exceptin: A prtable radiant heater which has a visible glwing heating element and which is nt sld r recmmended fr use as a basebard heater may be excluded as a basebard heater even if it meets the dimensinal specificatins in (b) abve. Such a heater may be judged under the requirements fr mvable air heaters in the Standard fr Mvable and Wall- r Ceiling-Hung Electric Rm Heaters, UL Fr this determinatin, a radiant heater is ne in which the visible prtin f the heating element attains a temperature f at least 650 C ( F) under nrmal cnditins f peratin. 0-

16 6 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, A prduct that cntains features, characteristics, cmpnents, materials, r systems new r different frm thse cvered by the requirements in this Standard, and that invlve a risk f fire, electric shck, r injury t persns shall be evaluated using the apprpriate additinal cmpnent and end-prduct requirements as determined necessary t maintain the acceptable level f safety as riginally anticipated by the intent f this Standard. A prduct whse features, characteristics, cmpnents, materials, r systems cnflict with specific requirements r prvisins f this Standard cannt be judged t cmply with this Standard. Where cnsidered apprpriate, revisin f requirements may be prpsed and adpted in cnfrmance with the methds emplyed fr develpment, revisin, and implementatin f this Standard. 2 Units f Measurement 2.1 If a value fr measurement as given in these requirements is fllwed by an equivalent value in ther units, the secnd value may be nly apprximate. The first stated value is the requirement. 3 Cmpnents 3.1 Except as indicated in 3.2, a cmpnent f a prduct cvered by this standard shall cmply with the requirements fr that cmpnent. See Appendix A fr a list f standards cvering cmpnents generally used in the prducts cvered by this standard. 3.2 A cmpnent need nt cmply with a specific requirement that: a) Invlves a feature r characteristic nt needed in the applicatin f the cmpnent in the prduct cvered by this standard, r b) Is superseded by a requirement in this standard. 3.3 A cmpnent shall be used in accrdance with its recgnized rating established fr the intended cnditins f use. 3.4 Specific cmpnents are recgnized as being incmplete in cnstructin features r restricted in perfrmance capabilities. Such cmpnents are intended fr use nly under limited cnditins, such as certain temperatures nt exceeding specified limits, and shall be used nly under thse specific cnditins fr which they have been recgnized. 3.5 Unless indicated therwise, all vltage and current values mentined in this standard are rms. CONSTRUCTION 4 Frame and Enclsure 4.1 The enclsure f basebard heating equipment shall prevent mlten metal, burning insulatin, flaming particles, r the like frm falling n flammable materials, including the surface upn which the enclsure is supprted. 4.2 The enclsure f basebard heating equipment designed fr permanent installatin, that is, intended fr permanent cnnectin t the pwer supply, shall be prvided with means and instructins fr munting in the intended manner. Any fittings such as brackets, hangers, r the like, necessary fr munting shall be furnished with the equipment.

17 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL :,,"', 4.3 The requirement in 4.1 necessitates use f a barrier f nnflammable material: a) Under a mtr unless: 1) The structural parts f the mtr r f the heater prvide the equivalent f such a barrier, 2) The prtectin prvided with the mtr is such that n burning insulatin r mlten material falls t the surface that supprts the heater when the mtr is energized under. each f the fllwing fault cnditins: i) Open main winding, ii) iii) Open starting winding, and Starting switch shrt-circuited. 3) The mtr is prvided with a thermal mtr prtectr (a prtective device that is sensitive t bth temperature and current) that will prevent the temperature f the. mtr windings frm becming mre than 125 C (255 F) under the maximum lad under which the mtr will run withut causing the prtectr t cycle, and frm becming mre than 150 C (300 F) with the rtr f the mtr lcked. b) Under wiring, unless it is f the flame-retardant type. Neprene-, asbests-, r thermplasticinsulated wires are cnsidered t be f this type. It will als necessitate that a switch, transfrmer, relay, slenid, r the like be individually and cmpletely enclsed except at terminals, unless it can be shwn that failure f the cmpnent wuld nt result in a risk f fire, r unless there are n penings in the bttm f the enclsure. An pening in the bttm f the enclsure is nt acceptable if it is lcated directly belw field- r factry-made splices r verlad r vercurrent prtective devices. 4.4 Except as indicated in 4.5, if penings are prvided in the enclsure f a heater r in an externally munted cmpnent intended fr permanent cnnectin t the pwer supply, they shall be s lcated that they will nt vent int cncealed spaces f a building structure such as int hllw spaces in the wall, when the equipment is installed as intended. 4.5 The requirement in 4.4 des nt apply t an pening fr a munting screw r nail r fr a manufacturing peratin (such as paint drainage) if: a) N such pening has a dimensin mre than 17/64 inch (6.7 mm) r an area mre than square inch (34.5 mm 2 ), and b) There is n mre than ne munting-screw hle fr each 12 inches (300 mm) f length r fractin theref in basebard heating equipment intended fr recessed installatin. 4.6 Except as nted in 4.7 an pening fr ventilatin in the enclsure; ther than in the bttm, f a heater and an pening assciated with the dissipatin f heated air frm the element shall be prvided with ne r mre baffles that will prevent the emissin f flame, mlten metal, burning insulatin, r the like frm the heater.

18 8 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, In a cmpartment ther than ne that huses an verlad r vercurrent prtective device, the baffles mentined in 4.6 may be mitted if: a) N ventilating pening in a vertical wall, ther than ne assciated with the dissipatin f heated air frm the elements during nrmal peratin f the heater, is mre than 3/8 inch (9.5 mm) in width, r b) The heater is s cnstructed that it is suitable fr the purpse, as shwn by apprpriate investigatin. 4.8 Cast- and sheet-metal enclsures shall cnfrm with the requirements f Tables Exceptin: A sheet steel enclsure may have a lesser thickness than specified in Table 4.1 but nt less than inch (24 MSG) (0.51 mm) when it is determined that the enclsure f lesser thickness due t its shape and use f reinfrcing members affrds the required prtectin. 4.9 Amng the factrs that shall be taken int cnsideratin when judging the acceptability f nnmetallic materials are resistance t: a) Mechanical damage, b) Impact, c) Misture absrptin, d) Cmbustin, and e) Distrtin at temperatures t which the material may be subjected under cnditins f nrmal r abnrmal use A plymeric material used fr the frame r enclsure shall cmply with the applicable requirements in the Standard fr Plymeric Materials - Use in Electrical Equipment Evaluatins, UL 746C. Exceptin: The abnrmal peratin tests in UL 1042 may be cnducted in lieu f the Abnrmal Operatin Test, Sectin 35, and Severe Cnditins Test, Sectin 24, f UL 746C Sheet metal t which a wiring system is t be cnnected in the field shall have an average thickness n less than inch (0.81 mm) if uncated steel, n less than inch (0.86 mm) if galvanized steel, and n less than inch (1.14 mm) if nnferrus At pints where the face f an attachment-plug receptacle prjects thrugh it, the enclsure shall have a thickness n less than: a) inch (0.81 mm) if f ferrus metal, b) inch (1.14 mm) if f nnferrus metal, and c) 0.10 inch (2.5 mm) if f insulating material, except that an enclsure f insulating material may be f lesser thickness if s frmed r reinfrced as t prvide adequate physical strength. The insulating material shall be nnflammable.

19 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Table 4.1 Minimum thickness f sheet metal fr electrical enclsures - carbn steel r stainless steel With supprting frame Withut supprting frame a r equivalent relnfrclng a Minimum thickness In Inches (mm) Maximum wlclth b Maximum lengthc Maximum wlclth b Maximum length Uncated Metal cated Inches (cm) Inches (cm) Inches (cm) Inches (cm) (MSG) (GSG) 4.0 (10.2) Nt limited 6.25 (15.9) Nt limited d (0.51) d (0.58) 4.75 (12.1) 5.75 (14.6) 6.75 (17.1) 8.25 (21.0) (24) (24) 6.0 (15.2) Nt limited 9.5 (24.1) Nt limited d (0.66) O.029 d (0.74) 7.0 (17.8) 8.75 (22.2) 10.0 (25.4) 12.5 (31.8) (22) (22) 8.0 (2O.3) Nt limited 12.0 (30.5) Nt limited (0.81) (0.86) 9.0 (22.9) 11.5 (29.2) 13.0 (33.0) 16.0 (40.6) (20) (20) 12.5 (31.8) Nt limited 19.5 (49.5) Nt limited (1.07) (1.14) 14.0 (35.6) 18.0 (45.7) 21.0 (53.3) 25.0 (63.5) (18) (18) 18.0 (45.7) Nt limited 27.0 (68.6) Nt limited (1.35) (1.42) 20.0 (50.8) 25.0 (63.5) 29.0 (73.7) 36.0 (91.4) (16) (16) a A supprting frame is a structure f angle r channel r a flded rigid sectin f sheet metal which is rigidly attached t and has essentially the same utside dimensins as the enclsure surface and which has sufficient trsinal rigidity t resist the bending mments which may be applied via the enclsure surface when it is deflected. Cnstructin that is cnsidered t have equivalent reinfrcing may be accmplished by designs that will prduce a structure which is as rigid as ne built with a frame f angles r channels. Cnstructin cnsidered t be withut supprting frame includes: 1) Single sheet with single frmed flanges (frmed edges), 2) A single sheet which is crrugated r ribbed, and 3) An enclsure surface lsely attached t a frame, that is, with spring clips. b The width is the smaller dimensin f a rectangular sheet metal piece which is part f an enclsure. Adjacent surfaces f an enclsure may have supprts in cmmn and be made f a single sheet. c Fr panels which are nt supprted alng ne side, fr example, side panels f bxes, the length f the unsupprted side shall be limited t the dimensins specified unless the side in questin is prvided with a flange at least 1/2 inch (12.7 mm) wide. d Sheet steel fr an enclsure intended fr utdr use shall cmply with the requirements fr utdr use equipment.

20 10 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11,1994 Table 4.2 Minimum thickness f sheet metal fr electrical enclsures - aluminum, cpper, r brass Withut supprting frame a With supprting frame r equivalent relnfrclng a Maximum wldth b Maximum lengthc Maximum wldth b Maximum length Inches (cm) Inches I (cm) Inches (cm) Inches I (cm) 3.0 (7.6) Nt limited 7.0 (17.8) Nt limited Minimum thickness Inches (mm) (AWG) d (0.58) (22) 3.5 ( 8.9) 4.0 I (10.2) 8.5 (21.6) 9.5 I (24.1) 4.0 (10.2) Nt limited 10.0 (25.4) Nt limited (0.74) (20) 5.0 (12.7) 6.0 I (15.2) 10.5 (26.7) 13.5 I (34.3) 6.0 (15.2) Nt limited 14.0 (35.6) Nt limited (0.91) (18) 6.5 (16.5) 8.0 I (20.3) 15.0 (38.1) 18.0 I (45.7) 8.0 (20.3) Nt limited 19.0 (48.3) Nt limited (1.14) (16) 9.5 (24.1) 11.5 I (29.2) 21.0 (53.3) 25.0 I (63.5) 12.0 (30.5) Nt limited 28.0 (71.1) Nt limited (1.47) (14) 14.0 (35.6) 16.0 I (40.6) 30.0 (76.2) 37.0 I (94.0) 18.0 (45.7) Nt limited 42.0 (106.7) Nt limited (1.91) (12) 20.0 (50.8) 25.0 I (63.4) 45.0 (114.3) 55.0 I (139.7) a A supprting frame is a structure f angle r channel r a flded rigid sectin f sheet metal which is rigidly attached t and has essentially the same utside dimensins as the enclsure surface and which has sufficient trsinal rigidity t resist the bending mments which may be applied via the enclsure surface when it is deflected. Cnstructin that is cnsidered t have equivalent reinfrcing may be accmplished by designs that will prduce a structure which is as rigid as ne built with a frame f angles r channels. Cnstructin cnsidered t be withut supprting frame includes: 1) Single sheet with single frmed flanges (frmed edges), 2) A single sheet which is crrugated r ribbed, and 3) An enclsure surface lsely attached t a frame, that is, with spring clips. b The width is the smaller dimensin f a rectangular sheet metal piece which is part f an enclsure. Adjacent surfaces f an enclsure may have supprts in cmmn and be made f a single sheet. c Fr panels which are nt supprted alng ne side, fr example, side panels f bxes, the length f the unsupprted side shall be limited t the dimensins specified unless the side in questin is prvided with a flange at least 1/2 inch (12.7 mm) wide. d Sheet metal fr an enclsure intended fr utdr use shall cmply with the requirements fr utdr use equipment.

21 APRIL 11,1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL (J Table 4.3 Cast-metal electric enclsures Minimum thickness, Inch (mm) Cast metal f ther Use, r dimensins f area Invlve~ Ole-cast metal than the die-cast type Ivea f 24 square inches (155 cm 2 ) r less and having n dimensin greater than 6 inches (152 mm) 1/16 (1.6) 1/8 (32.2) Ivea greater than 24 square inches r having any dimensin greater than 6 inches 3/32 (2.4) 1/8 (32.2) At a threaded cnduit hle 1/4 (6.4) 1/4 (6.4) At an unthreaded cnduit hle 1/8 (3.2) 1/8 (3.2) a The area limitatin fr metal 1/16 inch (1.6 mm) in thickness may be btained by the prvisin f reinfrcing ribs subdividing a larger area An electrical part shall be s lcated r enclsed that prtectin against unintentinal cntact. with uninsulated live parts will be prvided.,... '"... ~>t... ~ 4.14 The dr r cver f an enclsure shall be hinged: a) If it gives access t any fuse, circuit breaker, r manually resettable limit cntrl in ther than a lw-vltage circuit, and b) If uninsulated live parts are expsed during the replacement f the fuse r resetting f the manually resettable device. Such a dr r cver shall als be prvided with an autmatic latch (see 4.16) f the equivalent and, if live parts ther than the screw shell f a plug fusehlder are expsed inside the enclsure, a captive screw (r equivalent means requiring the use f a tl t pen) t secure the dr r cver in place A dr r cver giving access t any verlad-prtective device in ther than a lw-vltage circuit shall be tight-fitting and shall verlap the surface f the enclsure arund the pening A spring latch, a magnetic latch, a dimple, r any ther mechanical arrangement that will hld the dr in place and wuld require sme effrt n the user's part t pen it, is cnsidered t be an acceptable means fr hlding the dr in place as required in A cmpnent subject t inspectin, replacement, cleaning, r ther servicing shall be as accessible as practicable, and shall be fully accessible withut the use f special tls if it is intended t be manually perated r adjusted r if it will definitely require peridic servicing Parts f basebard heaters such as an enclsure, frame, guard, r handle, subject t cntact in peratin and user servicing shall be free f sharp crners, edges, r prjectins. See and

22 12 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, A handle intended t supprt r carry mre than 20 punds (9.07 kg) shall have a gripping surface at least 4 inches (100 mm) lng A handle shall be fastened s that it will nt be capable f being partly r cmpletely remved withut the use f a tl A handle used fr supprt f a prtable heater shall be able t sustain fur times the weight f the heater. The apprpriate lad shall be unifrmly applied ver a 3 inch (75 mm) length at the center f the handle, gradually increased t the test value ver a perid f 5 t 10 secnds, and maintained at the test value fr 1 minute. The lad shall be supprted with n evidence f damage t the handle (separatin, cracking, r permanent defrmatin). Fr this test the heater may be inverted and supprted s that the test weight can be applied directly t the handle If mre than ne handle is furnished n the heater, the lad indicated in 4.21 shall be distributed between the handles. The distributin f the lad shall be determined by measuring the percentage f the weight f the heater supprted by each handle with the heater in the intended carrying cnditin If a heater is furnished with mre than ne handle and the heater can be carried by ne handle alne, each handle shall be capable f supprting the lad described in Accessibility f Uninsulated Live Parts, Film-Cated Wire, and Mving Parts 5.1 In determining if an pening in an enclsure is acceptable, cnsideratin is t be given t: a) The prximity f uninsulated live parts (as determined by applying 5.3 and 5.4) and b) The pssibility f the emissin f burning insulatin, mlten metal, and the like thrugh the pening (as determined by applying ). 5.2 A mving part such as a fan blade, a blwer wheel, a pulley, a belt, r the like that may cause injury t persns shall be enclsed r guarded. 5.3 T reduce the likelihd f unintentinal cntact that may invlve a risk f: a) Electric shck frm an uninsulated live part r film-cated wire r b) Injury t persns frm a mving part, an pening in an enclsure shall cmply with either (1) r (2). 1) Fr an pening that has a minr dimensin (see 5.7) less than 1 inch (25.4 mm), such a part r wire shall nt be cntacted by the prbe illustrated in Figure ) Fr an pening that has a minr dimensin f 1 inch r mre, such a part r wire shall be spaced frm the pening as specified in Table 5.1. Exceptin: A mtr need nt cmply with these requirements if it cmplies with the requirements in 5.4.

23 APRIL 11,1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Figure 5.1 Articulate prbe with web stp I'-L I r-- I t '-~ l I \ -~ ~ ~ All. DIItENSIOHS IN I.IIWUETERS PAIOOA

24 14 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, With respect t a part r wire as mentined in 5.3, in an integral enclsure f a mtr as mentined in the exceptin t 5.3. a) An pening that has a minr dimensin (see 5.7) less than 3/4 inch (19.1 mm) is nt acceptable if: 1) A mving part can be cntacted by the prbe UJustrated in Figure 5.2, 2) Film-cated wire can be cntacted by the prbe illustrated in Figure 5.3, 3) In a directly accessible mtr (see 5.8), an uninsulated live part can be cntacted by the prbe illustrated in Figure 5.4, r 4) In an indirectly accessible mtr (see 5.8), an uninsulated live part can be cntacted by the prbe illustrated in Figure 5.2. b) An pening that has a minr dimensin f 3/4 inch r mre is acceptable if a part r wire is spaced frm the pening as specified in Table The prbes mentined in 5.3 and 5.4 and illustrated in Figures shall be applied t any depth that the pening will permit; and shall be rtated r angled befre, during, and after insertin thrugh the pening t any psitin that is necessary t examine the enclsure. The prbes illustrated in Figures 5.1 and 5.4 shall be applied in any pssible cnfiguratin; and, if necessary, the cnfiguratin shall be changed after insertin thrugh the pening. 5.6 The prbes mentined in 5.5 and 5.7 are t be used as measuring instruments t judge the accessibility prvided by an pening, and nt as instruments t judge the strength f a material; they are t be applied with the minimum frce necessary t determine accessibility. 5.7 With reference t the requirements in 5.3 and 5.4 and Table 5.1, the minr dimensin f an pening is the diameter f the largest cylindrical prbe that can be inserted thrugh the pening. 5.8 With reference t the requirements in 5.4: a) An indirectly accessible mtr is a mtr: 1} That is accessible nly by pening r remving a part f the uter enclsure, such as a guard r panel, that can be pened r remved withut using a tl, r 2} That is therwise guarded r enclsed s that it is unlikely t be cntacted. b) A directly accessible mtr is a mtr: 1) That can be cntacted withut pening r remving any part, r 2) That is lcated s as t be accessible t cntact.

25 APRIL 11,1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL (J Figure 5.2 Prbe fr mving parts and uninsulated live parts ANY CONVENIENT LENGTl-I 3/4" (19.1mm) DIA. 1/2" (12.7mm) DIA. PA140A J-- 4" (101.6mm) 1/4" (6.4mm) RAD.-~ Figure 5.3 Prbe fr film-cated wire ANY CONVENIENT LENGTH 1/2 INCH DIA. 3/4 INCH DIA. (12.7mm) (19.1mm) 9/16 INCH(14.3mm)-f INCHES ----1~ (101.6mm) PA130A 3/16 INCH R (4.8mm)

26 16 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11,1994 Figure 5.4 Articulate prbe Stp plate SECTION A-A 8-8 Spherical All Dimensins in Millimeters PA120-1 St'I-l--H-I--_II... T"_-..&;*~~..,ii:!!'~II-+-~r:: SECTION C-C Table 5.1 Minimum acceptable distance frm an pening t a part that may invlve a risk f electric shck r injury t persns a Minr dlmensln b f pening Minimum distance frm pening t pa~ Inches (mm) Inches (mm) 3/4 0 (19.1) 4-1/2 (114.0) 1 c (25.4) 6-1/2 (165.0) 1-1/4 (31.8) 7-1/2 (190.0) 1-1/2 (38.1) 12-1/2 (318.0) 1-7/8 (47.6) 15-1/2 (394.0) 2-1/8 (54.0) 17-1/2 (444.0) d 30 (762.0) a Fr an pening having a minr dimensin between tw values specified in the table, the distance frm the pening t the part shall nt be less than that determined by interplatin between the crrespnding values in the right-hand clumn. b See 5.7. C Any dimensin less than 1 inch applies t a mtr nly. d Mre than 2-1/8 inches, but nt mre than 6 inches (152.0 mm).

27 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL C) 5.9 During the examinatin f a prduct t determine whether it cmplies with the requirements in 5.3 r 5.4, a part f the enclsure that may be pened r remved by the user withut using a tl (t attach an accessry, t make an perating adjustment, r fr ther reasns) is t be pened r remved With reference t the requirements in 5.3 and 5.4, insulated brush caps are nt required t be additinally enclsed If the pening r remval f a dr, a panel, r a shield will expse any mving part that/can cause injury t persns, the pening r remval f the dr, panel, r shield shall: a) Require the use f tls, r b) Cause an interlcking device nt likely t be unintentinally rendered ineffective t stp the mving part A mving part is nt t be cnsidered when judging cmpliance with 5.3 r 5.4 if the part is unlikely t be cntacted thrugh the pening because f fixed cmpnents, including baffles. 6 Parts Subject t Pressure 6.1 The requirements f 44.1 apply t parts which are 6 inches (150 mm) r less in inside diameter. 6.2 Fr determining criteria fr testing see Sectin 44, Hydr-Static Pressure Test. 6.3 A means fr safely relieving pressure shall be prvided fr all parts in which pressure might be generated in the event f fire. 6.4 Pressure-relief devices (see 6.10), fusible plugs, sldered jints, nnmetallic tubing, r ther pressurerelief means r the equivalent may be emplyed t cmply with the requirement in 6.3., 6.5 There shall be n shutff valve between the pressure-relief means and the part(s) that it is intended t prtect. 6.6 A vessel having an inside diameter f mre than 3 inches (75 mm)' and subject t air r steam pressure generated r stred within the appliance shall be prtected by a pressure-relief device. 6.7 The start-t-discharge pressure setting f the pressure-relief device shall be n higher than the marked maximum wrking pressure f the vessel. The discharge rate f the device shall be capable f relieving the pressure. 6.8 A pressure-relief device shall cmply with all fur f the fllwing: a) Shall be cnnected as clse as pssible t the pressure vessel r parts f the system that it is intended t prtect. b) Shall be s installed that it is fully accessible fr inspectin and repair, and cannt be readily rendered inperative, (J c) Shall have its discharge pening s lcated and directed that the risk f scalding has been reduced t an acceptable degree, and d) Shall have its discharge pening s lcated and directed that peratin f the device will nt depsit misture n bare live parts, r n insulatin r cmpnents affected detrimentally by misture.

28 18 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, A pressure-relief device having an adjustable setting is t be judged n the basis f its maximum setting unless the adjusting means is sealed at a lwer setting A pressure-relief device is cnsidered t be a pressure-actuated valve r rupture member designed t relieve excessive pressures autmatically If a pressure-relief device is required, the electrical cntrl respnsible fr limiting the pressure in the vessel shall be capable f perfrming under rated lad fr 100,000 cycles f peratin and shall prevent the pressure frm exceeding 90 percent f the relief-device setting during any f the tests required by this standard. 7 Assembly 7.1 A switch, a lamphlder, an attachment-plug receptacle, a mtr-attachment plug, r similar cmpnent shall be munted and secured in place and, except as nted in 7.2 and 7.3, shall be prevented frm turning. See The requirement that a switch be prevented frm turning may be waived if all fur f the fllwing cnditins are met: a) The switch is f a plunger r ther type that des nt tend t rtate when perated (a tggle switch is cnsidered t be subject t frces that tend t turn the switch during the peratin f the switch). b) The means f munting the switch is nt subject t lsening as the result f its peratin. c) The spacings are nt reduced belw the minimum acceptable values if the switch rtates, and d) The peratin f the switch is by mechanical means rather than direct cntact by persns. 7.3 A lamphlder f a type in which the lamp cannt be replaced, such as a nen pilt r indicatr light in which the lamp is sealed in a nnremvable jewel, need nt be prevented frm turning if rtatin cannt reduce spacings belw the minimum acceptable values. 7.4 The means fr preventing the turning mentined in 7.1 is t cnsist f mre than frictin between surfaces; fr example, a lck washer, prperly applied, is acceptable as means t prevent turning f a small stem-munted switch r ther device having a single-hle munting means. 7.5 Uninsulated live parts shall be secured t the base r munting surface s that they will be prevented frm turning r shifting if such mtin may result in a reductin f spacings belw the minimum acceptable values specified in Frictin between surfaces is nt acceptable as a means t prevent shifting r turning f live parts, but a lck washer is acceptable. 8 Air-Handling Cmpartments 8.1 Expsed unimpregnated asbests material shall nt be used in an air-handling cmpartment. The unprtected edge f a gasket sandwiched between tw parts is cnsidered t be expsed.

29 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Prtectin Against Crrsin 9.1 Irn and steel parts shall be prtected against crrsin by enameling, galvanizing, plating, r ther equivalent means if the crrsin f such unprtected parts culd result in a risk f fire r electric shck. Exceptin: Cast-irn parts are nt required t be prtected against crrsin. A sheath emplyed n a heating element perating in' air and terminal parts attached directly t the heating element need nt be prtected against crrsin. 9.2 The aging characteristics f plating r ther finish used in a heater shall be such that deteriratin f the finish will nt result eventually in unacceptable perfrmance f the heater. 9.3 The sheath f an immersin-type heating element shall be f a metal resistant t crrsin by the liquid in which the element is intended t be immersed. 10 Permanently Cnnected Equipment 10.1 General Permanently cnnected equipment (intended fr permanent cnnectin t the pwer supply) shall have prvisin fr cnnectin f ne f the wiring systems that, in accrdance with the Natinal Electrical Cde, ANSIjNFPA , wuld be applicable t the appliance The lcatin f a terminal bx r cmpartment in which pwer-supply cnnectins t permanently cnnected equipment are t be made shall be such that these cnnectins may be inspected after the equipment is installed as intended A terminal cmpartment intended fr the cnnectin f a supply raceway shall be attached t the equipment s as t be prevented frm turning with respect t it A knckut hle r threaded hub fr cnnectin f a cnduit field-wiring system t a field-wiring cmpartment shall accmmdate cnduit f the trade size determined by applying Table If threads fr the cnnectin f cnduit are tapped all the way thrugh a hle in an enclsure wall r if an equivalent cnstructin is emplyed, there shall nt be less than three nr mre than five threads in the metal, and the cnstructin f the device shall be such that a cnduit bushing can be attached. If threads fr the cnnectin f cnduit are nt tapped all the way thrugh a hle in an enclsure wall, cnduit hub, r the like, there shall nt be less than 3-1/2 threads in the metal, and there shall be a smth, runded inlet hle fr the cnductrs that will affrd prtectin t the cnductrs equivalent t that prvided by a standard cnduit bushing and will have an internal diameter apprximately the same as that f the crrespnding trade size f rigid cnduit A knckut in a sheet-metal enclsure cnfrming with the requirements f 10.1,.7 shall be capable f being remved withut defrmatin f the enclsure t the extent that it wuld affect the attachment f a cnduit fitting, may result in reductin f electrical spacings belw the minimum acceptable values, r bth. C) A knckut shall remain in place when a frce f 10 punds (44.5 N) is applied at right angles t the knckut by a 1/4 inch (6.4 mm) diameter mandrel with a flat end. The mandrel shall be applied at the pint mst likely t cause mvement f the knckut.

30 20 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, 1994 Table 10.1 Trade size f cnduit in inches 8 (mm 00) Wire size Number f wires AWG mm /2 (21.3) 1/2 (21.3) 1/2 (21.3) 1/2 (21.3) 1/2 (21.3) /2 (21.3) 1/2 (21.3) 1/2 (21.3) 3/4 (26.7) 3/4 (26.7) /2 (21.3) 1/2 (21.3) 1/2 (21.3) 3/4 (26.7) 3/4 (26.7) /4 (26.7) 3/4 (26.7) 3/4 (26.7) 1 (33.4) 1 (33.4) /4 (26.7) 1 (33.4) 1 (33.4) 1-1/4 (42.3) 1-1/4 (42.3) a This table is based n the assumptin that all cnductrs will be f the same size and there will be n mre than six cnductrs in the cnduit. If mre than six cnductrs will be iiwlved r if all f them are nt f the same size, the internal crss-sectinal area f the smallest cnduit that may be used is determined by multiplying by 2.5 the ttal crss-sectinal area f the wires, based n the crss-sectinal area f Type THW wire A knckut shall be prvided with a flat surrunding surface fr seating f a cnduit bushing and shall be lcated s that installatin f a bushing at any knckut likely t be used during installatin will nt result in spacings between uninsulated live parts and the bushing less than thse required by this standard. In applying the spacing requirement, the bushing is cnsidered t be part f the enclsure. The area f the flat surface surrunding the pening shall be capable f accmmdating the bushing and lcknut intended t be used with the largest size cnduit that can be installed. See Table In measuring a spacing between an uninsulated live part and a bushing installed in the knckut referred t in , it is t be assumed that a bushing having the dimensins indicated in Table 10.3 is in place, in cnjunctin with a single lcknut installed n the utside f the enclsure Space shall be prvided in the field wiring utlet bx r cmpartment fr installatin f the cnductrs f the number and size required by using Type TW r THW wire (except that ther types f cnductrs may be used when specified in the installatin instructins) when at least a 6-inch (150 mm) length f each cnductr is brught int the wiring cmpartment. If necessary, a trial installatin is t be made An pening fr the entry f a cnductr r cnductrs in a lw-vltage circuit as described in shall be prvided with insulating bushings. The bushings may be munted in place in the pening r may be prvided with the enclsure s that they may be munted when the equipment is installed. Exceptin: A bushing is nt required if the heater is marked t indicate that field wiring in the lw-vltage circuit is t be installed in Class 1, in accrdance with the Natinal Electrical Cde, NFPA A bushing f rubber r rubber-like material prvided in accrdance with shall be 1/8 inch (3.2 mm) r mre in thickness. A hle in which such a bushing is munted shall be free frm sharp edges, burrs, r prjectins which may damage the bushing. Exceptin N.1: The bushing may be nt less than 3/64 inch (1.2 mm) minimum thickness if the metal arund the hle is eyeletted r treated t ensure smth edges. Exceptin NO.2: A tab resulting frm remval f a cnduit knckut is nt cnsidered a burr r prjectin when applying this requirement.

31 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT UL Table 10.2 Diameter f knckut and width f surrunding flat surface Trade size Knckut Minimum width f flat surface f cnduit d1ameter'i surrunding knckut Inches (mm 00) Inches (mm) Inch (mm) 1/2 (21.3) 7/8 (22.2) 0.13 (3.4) 3/4 (26.7) 1-3/32 (27.8) 0.16 (4.1) 1 (33.4) 1-23/64 (34.5) 0.21 (5.2) 1-1/4 (42.3) 1-23/32 (43.7) 0.28 (7.1) a Knckut diameters will be measured ther than at pint where a tab may remain after remval f knckut. Table 10.3 Dimensins f bushings 10.2 Wiring terminals Trade size f cnduit, Inches (mm 00) 1/2 (21.3) 3/4 (26.7) 1 (33.4) 1-1/4 (42.3) Bushing dimensins, Inches (mm) Overall diameter 1 (25.4) 3/8 1-15/64 (31.4) 27/ /32 (40.5) 33/ /16 (49.2) 9/16 Height ( 9.5) (10.7) (13.1) (14.3) Equipment intended fr permanent cnnectin t the pwer supply shall be prvided with fieldwiring terminals r leads fr cnnectin f the pwer-supply cnductrs. Each terminal r lead shall be sized fr cnnectin f a cnductr having an ampacity, accrding t the Natinal Electrical Cde, ANSljNFPA , n less than 125 percent f the rated current at the terminal r lead; if such rating is 24 amperes r less, the terminal r lead shall be sized fr cnnectin f a N. 10 AWG (5.3 mm 2 ) cpper wire, except as indicated in and If the equipment is als t be field-cnnected with aluminum cnductrs, the terminal r lead shall als be rated fr cnnectin f a NO.8 AWG (8.4 mm 2 ) aluminum wire except as indicated in and A lead shall be n mre than tw standard wire sizes smaller than the branch-circuit pwer-supply cnductr (cpper) t which it will be cnnected. See A lead intended fr cnnectin t an external circuit shall be prvided with a strain relief if stress n the leads may cause the lead t separate frm its terminatin, r result in damage t the lead frm sharp edges. Cnnectins which are welded, mechanically secured and sldered, r securely crimped, are cnsidered as nt likely t separate due t such stress Leads prvided fr spliced cnnectins t an external high-vltage circuit shall nt be cnnected t wire-binding screws r pressure terminal cnnectrs lcated in the same cmpartment as the splice unless the screws r cnnectrs are rendered unuseable fr field wiring cnnectins.

32 22 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, Equipment rated 16 amperes r less, which is nt arranged fr cnnectin f N. 10 AWG (5.3 mm~ (cpper) pwer-supply cnductrs, shall be arranged fr cnnectin t a 15- r 20-ampere branch circuit, as apprpriate fr the rating f the equipment, and shall be marked in accrdance with In determining the size f the pwer-supply cnductrs in equipment intended fr cnnectin t multiple pwer supplies and in which it is likely that mre than six such cnductrs will ccupy the same raceway, the additinal ampacity deratings given in the Natinal Electrical Cde, ANSIjNFPA , shall be applied Fr the purpse f these requirements, field-wiring terminals are cnsidered t be the terminals t which pwer-supply, cntrl, r equipment-grunding cnnectins will be made in the field when the equipment is installed A field-wiring terminal r lead fr cnnectin f an equipment-grunding cnductr shall be prvided. See A field-wiring terminal intended slely fr cnnectin f an equipment-grunding cnductr shall be capable f securing a cnductr f the size fr the particular applicatin, in accrdance with the Natinal Electrical Cde, ANSI/NFPA See A field-wiring terminal shall be prvided with a pressure wire cnnectr fastened in place by being blted r held by a screw. Exceptin: A wire-binding screw may be emplyed at a field-wiring terminal intended t accmmdate a N. 10 AWG (5.3 mm 2 ) r smaller cnductr if upturned lugs r the equivalent are prvided t hld the wire in psitin A field-wiring terminal shall be prevented frm turning r shifting in psitin by means ther than frictin between surfaces. This may be accmplished by tw screws r rivets; by square shulders r mrtices, by a dwel pin, lug, r ffset; by a cnnecting strap r clip fitted int an adjacent part; r by sme ther equivalent methd A wire-binding ss:rewat a field-wiring terminal shall nt be smaller than N. 10 (4.8 mm diameter), except that a N.8 (4.2 mm diameter) screw may be used at a terminal intended nly fr the cnnectin f a N. 14 AWG (2.1 mm 2 ) cnductr, and a N.6 (3.5 mm diameter) screw may be used fr the cnnectin f a N. 16 AWG (1.3 mm 2 ) r N. 18 AWG (0.82 mm 2 ) cntrl-circuit cnductr It shuld be nted that accrding t the Natinal Electrical Cde, ANSI/NFPA , N. 14 AWG (2.1 mm 2 ) is the smallest cnductr which may be used fr branch-circuit wiring, and thus is the smallest cnductr that may be anticipated at a terminal fr the cnnectin f a pwer-supply wire A terminal plate tapped fr a wire-binding screw shall be f metal n less than inch (1.3 mm) in thickness, except that a plate n less than inch (0.8 mm) in thickness is acceptable if the tapped threads have tw r mre full threads in the metal, which may be extruded if necessary t prvide the threads Upturned lugs ra cupped washer shall be capable f retaining a cnductr f the size mentined either in , but n smaller than N. 14 AWG (2.1 mm 2 ) r in 11.21, whichever is applicable, under the head f the screw r the washer A wire-binding screw shall thread int metal.

33 \ APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Equipment prvided with field-wiring terminals r leads and intended t be cnnected t a grunded pwer-supply cnductr shall have ne terminal r lead identified fr the cnnectin f that cnductr if necessary because f the requirement in 21.4, 22.1, 23.4, r A field-wiring terminal intended fr the cnnectin f a grunded cnd uctr shall be f r plated with a metal substantially white in clr and shall be distinguishable frm the ther terminals, r identificatin f that terminal shall be shwn in sme ther manner, such as n an attached wiring diagram. A lead intended fr the cnnectin f a grunded cnductr shall be finished t shw a white r natural grey clr and shall be distinguishable frm the ther leads The surface f an insulated lead intended slely fr the cnnectin f an equipment-grunding cnductr shall be green with r withut ne r mre yellw stripes, and n ther lead ther than a grunding lead shall be s identified The requirements in and relating t clr cding f a lead fr identificatin d nt apply t internal wiring that is nt visible in a wiring cmpartment in the area in which field cnnectins are t be made. These requirements als d nt apply t leads r wiring f lw-vltage circuits intended t be field-cnnected t Class 2 wiring and which are separated r segregated frm high-vltage circuit field-wiring cnnectins by barriers A wire-binding screw intended fr the cnnectin f an equipment-grunding cnductr shall have a green-clred head that is hexagnal-shaped, sltted, r bth. A pressure wire cnnectr intended fr cnnectin f such a cnductr shall be identified, such as by being marked G, GR, Grund, Grunding, r the like, r by a marking n a wiring diagram prvided n the equipment. The wire-binding screw r pressure wire cnnectr shall be s lcated that it is unlikely t be remved during servicing' f the equipment Except as nted in the free length f a lead inside an utlet bx r wiring cmpartment shall be 6 inches (150 mm) r mre if the lead is intended fr field cnnectin t an external circuit The lead may be less than 6 inches (150 mm) in length if it is evident that the use f a lnger lead might result in damage t the lead insulatin. 11 Crd-Cnnected Heaters 11.1 General A prtable heater shall have a mass f n mre than 65 punds (29 kg), and n dimensin f such a heater shall be greater than 8 feet (2.4 m) A prtable heater shall be prvided with a directly attached flexible crd and an attachment-plug cap shall be prvided n the crd fr attachment t the supply circuit. The expsed length f the crd (including fittings) shall be n less than 6 feet (1.8 m) and n mre than 8 feet (2.4 m) The attachment plug cap shall be rated fr general use The flexible crd shall be as indicated in Table 10.4 r shall be f a type having such prperties that it will be at least equally serviceable fr the particular applicatin.

34 24 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11,1994 Table 10.4 Acceptable types f crd Temperature f mre than 121 c (250 f) n any surface liable t be cntacted by crd HPD, HPN, HSJO, HSJ Temperature f 121 c (250 f) r less n all surfaces liable t be cntacted by crcfl SP-2; SPT-2, SVO, SV, SVTO, SVT, SJO, SJ, SJTO, SJT a Crds f the types indicated in the first clumn may als be used The ampacity f the flexible crd shall be nt less than the current rating f the heater, and the current rating f the attachment-plug cap shall be n less than 125 percent f the current rating f the heater, except that a 15-ampere cap is acceptable fr a heater rated at n mre than 1500 watts at 120 vlts, r 3000 watts at 240 vlts, and a 20-ampere cap is acceptable fr a heater rated at n mre than 4000 watts at 240 vlts Supplementary insulatin n a flexible crd shall nt extend mre than 1/2 inch (13 mm) utside the heater (unless prvided with additinal mechanical prtectin), shall be prevented frm fraying r unraveling, and shall nt adversely affect the means fr prviding strain relief Strain relief Strain relief shall be prvided t prevent a mechanical stress n a flexible supply crd frm being transmitted t terminals, splices, r interir wiring Means shall be prvided t prevent the flexible crd frm being pushed int the enclsure f a heater thrugh the crd-entry hle if such displacement may: a) Subject the crd t mechanical damage,. b) Expse the crd t a temperature higher than that fr which it is rated, r c) Reduce spacings (such as t a metal strain-relief clamp) belw the minimum acceptable values A knt in the supply crd shall nt serve as the strain relief means with a metallic enclsure Bushings At a pint where a flexible crd passes thrugh an pening in a wall, barrier, r enclsing case, there shall be a bushing r the equivalent that shall be secured in place, and shall have a smth, runded surface against which the crd may bear. If Type SP-2, SPT-2, r ther crd lighter than Type HSJ is emplyed, if the wall r barrier is f metal, and if the cnstructin is such that the crd may be subjected t strain r mtin, and insulating bushing shall be prvided. The heat- and misture-resistant prperties f the bushing material shall be rated fr the particular applicatin.

35 \ \ " \ ---'---~ ' APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL (J If the crd hle is in wd, prcelain, phenlic cmpsitin, r equivalent nncnducting material, a smth runded surface is cnsidered t be equivalent t a bushing Ceramic materials and sme mlded cmpsitins are acceptable fr insulating bushings; but a separate bushing f wd, ht-mlded shellac-and-tar cmpsitin, r rubber material (ther than in a mtr) is nt acceptable. Vulcanized fiber may be emplyed if the bushing is n less than 3/64 inch (1.2 mm) thick and if it is frmed and secured in place s that it will nt be adversely affected by misture cnditins An insulated metal grmmet may be accepted in place f an insulating bushing if the insulating material used is n less than 1/32 inch (0.8 mm) thick and fills cmpletely the space between the grmmet and the metal in which it is munted In a prtable heater with a crd f a type fr which an insulating bushing is nt required, a smth~ edged hle, free frm burrs, fins, and the like, is cnsidered t be the equivalent f a bushing. 12 Current-Carrying Parts 12.1 Metal emplyed fr a current-carrying part shall be the fllwing r equivalent: a) Plated irn r steel, where the intended perating temperature f the part is mre than 100 C (212 F); r b) Stainless steel r ther crrsin-resistant ally, regardless f the part's intended perating temperature. Hwever, plain (unplated) irn r steel shall nt be used, regardless f temperatures attained by the part. Exceptin: Ordinary irn r steel having n additinal prtectin against crrsin may be emplyed fr a heating-element terminal part in accrdance with 9.1, and rdinary irn r steel having a crrsinresistant cating may be used fr any current-carrying part, regardless f its perating temperature, as fllws: a) Within a mtr r assciated gvernr. b) On a cntrl device such as a cmbinatin tip-ver and thermstat cntrl. c) Fr a welded-n cnnectin t any terminal f a cntrl device referenced in (b) r t terminals f a heating element assembly. 13 Internal Wiring 13.1 General The internal wiring shall cnsist f wires f a size and f a type r types that are rated fr the particular applicatin, when cnsidered with respect t the temperature and vltage t which the wiring is liable t be subjected, with respect t its expsure t il r grease, and with respect t ther cnditins f service t which it is liable t be subjected. The thickness f the insulatin shall be 1/32 inch (0.8 mm) r mre: except that it may be n less than 1/64 inch (0.4 mm) if the wire 'is prvided with a braid r jacket n less than 1/64 inch thick, r is a standard building wire prvided with a braid r jacket.

36 26 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, Fr the purpse f these requirements, the internal wiring f basebard heating equipment is cnsidered t be all the wiring beynd the pint where the pwer-supply crd f a crd-cnnected heater enters the enclsure, r beynd the wiring terminals r leads fr pwer-supply cnnectin f a permanently cnnected heater, even thugh sme f such wiring may nt be cmpletely enclsed and even thugh sme f it may be in the frm f flexible crd There is n temperature limit applicable t a cnductr (except as nted in C2 and C3 f Table 33.1) prvided with beads f nncarbnizable material r the equivalent Insulated wire emplyed fr internal wiring shall be standard building wire, fixture wire, appliancewiring material, r flexible crd rated fr the particular applicatin Prtectin f wiring The internal wiring (see ) shall be prtected r enclsed, except that a length f flexible crd may be emplyed fr external cnnectins, r fr internal cnnectins that may be expsed during servicing, if flexibility f the wiring is essential The wiring between the end f the element and the wiring cmpartment need nt be enclsed in a metal raceway if: a) It is enclsed: 1) In impregnated-glass fiber sleeving n less than inch (0.38 mm) thick, with the impregnatin rated fr the temperature attained n the wire, 2) In unimpregnated-glass fiber sleeving n less than inch (0.51 mm) thick, r 3) In ther equivalent sleeving r tubing, and b) The wiring insulatin is n less than 1/32 inch (0.8 mm) thick and the expsed length f wiring is n mre than 1 inch (25.4 mm) Internal wiring that is expsed thrugh an pening in the enclsure is cnsidered t be prtected as required in if, when judged as thugh it were enamel-insulated wire, the wiring wuld be acceptable accrding t 3.13 and Accessibility f Uninsulated Live Parts, Film-cated Wire, and Mving Parts, Sectin 4. Internal wiring within an enclsure is acceptable if, even thugh it can be tuched with the prbe, it is s prtected r guarded that it cannt be grasped r hked in such a manner that it culd be subjected t stress If the wiring is s lcated that it may be in prximity t flammable material r may be subjected t physical damage, it shall be in metal-clad cable, rigid metal cnduit, electrical metallic tubing, metal raceway, r shall therwise be equivalently prtected Wiring shall be prtected frm sharp edges (including male screw threads), burrs, fins, mving parts, and ther agencies that might abrade the insulatin n cnductrs A hle by means f which insulated wires pass thrugh a sheet-metal wall within the verall enclsure shall be prvided with a smth runded bushing r shall have smth well-runded surfaces upn which the wires may bear, t prevent abrasin f the insulatin. A flexible crd used fr external intercnnectin as mentined in shall be prvided with bushings and strain relief in accrdance with 11.2 and unless the cnstructin is such that the crd will be prtected frm stress r mtin.

37 -----~---- APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL If relative mtin ccurs between asbests-insulated wire and metal thrugh which the wire passes because f expansin and cntractin resulting frm changes in temperature, the pening shall be fitted with an insulating bushing r the equivalent Splices All splices and cnnectins shall be mechanically secure and bnded electrically. A sldered cnnectin shall be made mechanically secure befre being sldered if breaking r lsening f the cnnectin may result in any hazardus cnditin A splice shall be prvided with insulatin equivalent t that f the wires invlved if permanence f spacing between the splice and ther metal parts is nt ensured Insulatin cnsisting f tw layers f frictin tape, f tw layers f thermplastic tape, r f ne layer f frictin tape wrapped ver ne layer f rubber tape is acceptable n a splice. Thermplastic tape wrapped ver a sharp edge is nt acceptable The means f cnnecting stranded internal wiring t a wire-binding screw shall be such that lse strands f wire will be prevented frm cntacting ther live parts nt always f the same plarity as the wire and frm cntacting dead metal parts. This may be accmplished by use f pressure terminal cnnectrs, sldering lugs, crimped eyelets, sldering all strands f the wire, r the like Separatin f circuits Cnductrs f different circuits used in internal wiring, including insulated wires used in a terminal bx r cmpartment, shall either be: a) Prvided with insulatin rated fr the highest vltage invlved, r b) Shall be separated by a barrier r spacing frm an uninsulated live part cnnected t a different circuit Lw-vltage and high-vltage circuits, fr example, are cnsidered t be different circuits with reference t the requirement in Segregatin f insulated cnductrs may be accmplished by clamping, ruting, r an equivalent means that ensures permanent separatin frm insulated r uninsulated live parts f a different circuit., Except as nted in and , barriers shall be prvided t separate cnductrs that will be field-installed frm: - a) Cnductrs f any ther circuit that will be field-installed, b) Cnductrs f any ther circuit that are factry-installed, c) Uninsulated live parts f any ther circuit, and d) live parts f the same circuit if unsafe peratin can result frm Shrt-circuiting f the live parts The barriers mentined in (a) and (b) are nt required if the cnductr invlved are, r will be, insulated fr the maximum vltage f either circuit.

38 28 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, The barriers mentined in (c) and (d) are nt required if the field-installed cnductrs will be rated fr general wiring r fixture wires rated fr 600 vlts If the field-installed cnductrs will have insulatin less than that fr the cnductrs described in , the barrier mentined in (d) is nt required if the circuit is lw-vltage and if shrt-circuiting f the live parts will nt result in a risk f fire r electric shck With respect t (a) and (b) a remvable barrier r ne having penings fr the passage f cnductrs may be emplyed, prvided instructins fr the use f the barrier are a permanent part f the appliance. If cmplete instructins, in cnjunctin with a wiring diagram, will prvide fr the designated separatin f the high-vltage and lw-vltage circuits, the barrier may be mitted Segregatin f field-installed cnductrs frm ther field-installed cnductrs and frm uninsulated live parts f the heater cnnected t different circuits may be accmplished by arranging the lcatin f the penings in the enclsure fr the varius cnductrs, with respect t the terminals r ther uninsulated live metal parts, s that there is n likelihd f the intermingling f the cnductrs r parts f different circuits. a) If the number f penings in the enclsure des nt exceed the minimum required fr the intended wiring f the heater and if each pening is lcated ppsite a set f terminals, it is t be assumed, fr the purpse f determining cmpliance with , that the cnductrs entering each pening will be cnnected t the terminals ppsite the pening. b) If mre than the minimum number f penings are prvided, there shall be n likelihd f cnductrs entering at pints ther than ppsite the terminals t which they are intended t be cnnected and cntacting insulated cnductrs r uninsulated current-carrying parts cnnected t a different circuit T determine if a heater cmplies with the requirement in , it is t be wired as it wuld be in service. In s ding, slack is t be left in each cnductr within the enclsure, and this slack is t be stwed in the wiring cmpartment A circuit classified as lw-vltage is ne invlving a ptential f nt mre than 3D-vlts, alternatingcurrent (42.4 peak) r direct current and supplied by a primary battery r by a Class 2 transfrmer r by a cmbinatin f transfrmer and fixed impedance which, as a unit, cmplies with all the perfrmance requirements fr a Class 2 transfrmer A circuit derived frm a surce f supply classified in as a high-vltage circuit, by cnnecting resistance in series with the supply circuit as a means f limiting the vltage and current, is nt cnsidered t be a lw-vltage circuit as described in A circuit classified as high-vltage is ne invlving a ptential f nt mre than 600 vlts and having circuit characteristics in excess f thse f a lw-vltage circuit A metal barrier shall have a thickness at least as great as the required thickness f the enclsure metal. A barrier f insulating material (see Sectin 15, Electrical Insulatin) shall have a minimum thickness f inch (0.71 mm) Unclsed penings in a barrier fr the passage f cnductrs shall be n larger in diameter than 1/4 inch (6.4 mm) and shall nt exceed in number, n the basis f ne pening per cnductr, the number f wires that will need t pass thrugh the barrier. The clsure fr any ther pening shall present a smth surface wherever an insulated wire may be in cntact with it; and the area f any such pening, with the clsure remved, shall be n larger than required fr the passage f the necessary wires..

39 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EaUIPMENT - UL () 14 Heating Elements 14.1 A heating element shall be supprted s as t prevent sagging, lsening, and ther adverse cnditins f the element resulting frm: a) Cntinuus heating, r b) Flexing f the element supprts r related wiring due t alternate heating and cling f the element. 15 Electricallnsulatin 15.1 Material fr the munting f current-carrying parts shall be f misture resistant material such as prcelain, phenlic, r cld-mlded cmpsitin Vulcanized fiber may be used fr the insulating bushings, washers, separatrs, and barriers but nt as the sle supprt fr uninsulated live parts f ther than lw-vltage circuits Magnesium xide and asbests cmpunds are acceptable fr electrical insulatin nly when prtected against mechanical damage and absrptin f misture such as in sheathed heater elements. 16 Thermal Insulatin 16.1 Thermal insulatin shall be f such nature and s lcated. and munted r supprted that it will nt be adversely affected by any intended peratin f the heater. See als Thermal insulatin that is nt rigid shall be s munted r supprted that it will nt sag. Adhesive material emplyed fr munting thermal insulatin shall be rated fr use at the temperature t which it may be subjected Determinatin f the quality f an adhesive may be mitted if the thermal insulatin is mechanically supprted by at least ne rivet r the equivalent per square ft f material (at least 11 rivets r the equivalent per square meter f material) Flammable thermal insulatin shall nt be acceptable if it is s lcated that it may be in a current f air within the heater Flammable r electrically cnductive thermal insulatin shall nt make cntact with uninsulated live parts f a heater. 17 Mtrs 17.1 A mtr shall be capable f handling its maximum intended lad withut intrducing any risk f fire r electric shck A mtr winding shall resist the absrptin f misture. Enameled wire is nt required t be additinally treated t prevent absrptin f misture, but fiber slt liners, clth cil wrap, and similar. misture-absrptive materials shall be prvided with impregnatin r therwise treated t prevent misture absrptin.

40 30 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, Mtr Overlad Prtectin 18.1 A heater emplying a fractinal-hrsepwer mtr [ne having a frame diameter f 7 inches (180 mm) r less] and intended t be remtely r autmatically cntrlled, and a permanently cnnected, cntinuus-duty, manually started heater emplying a fractinal-hrsepwer mtr [ne having a frame diameter f 7 inches r less] shall incrprate thermal r verlad prtectin that will prevent the mtr frm attaining excessively high temperatures under any perating cnditins. See When a mtr is perating under the maximum verlad that it can carry withut causing the prtective device t functin, the maximum acceptable temperature n a Class 105 (Class A) insulated mtr winding is 140 C (284 F); except that this cnsideratin des nt apply t a mtr mving air nly by means f a fan r blwer directly attached t the mtr shaft. Fr a mtr emplying Class 130 (Class B) insulatin, the crrespnding acceptable temperature is 165 C (329 F) When the rtr f a mtr is lcked, the maximum acceptable temperature n a Class 105 (Class A) insulated mtr winding is 200 C (392 F) during the first hur f peratin and is 175 C (347 F) thereafter. After the first hur f peratin, the average temperature [the average f: a) The arithmetic mean f the maximum temperatures, and b) The arithmetic mean f the minimum temperatures] is nt acceptable if it is higher than C (302 OF). Fr a mtr emplying Class 130 (Class B) insulatin, the crrespnding temperatures are 225 C (437 F) fr the first hur, 200 C after the first hur, and 175 C fr the mean temperature Ordinarily, a mtr having thermal prtectin r impedance prtectin cmplying with the requirements fr such prtectin is cnsidered t cmply with the requirements in Overcurrent Prtectin 19.1 A heater rated at mre than 48 amperes shall have the heating elements subdivided. Each subdivided circuit shall nt exceed 48 amperes and shall be prtected at nt mre than 60 amperes The vercurrent prtective devices required by 19.1 shall be prvided as an integral part f the equipment r shall be prvided as a separate assembly (fr independent munting) fr use with the equipment. See The vercurrent prtectin mentined in , 19.7, and 19.8 shall be f a type recgnized in the Natinal Electrical Cde, ANSI/NFPA , fr branch-circuit prtectin A mtr, except as indicated in 19.5 in a heater rated at mre than 16 amperes shall be prtected by an vercurrent device having a maximum ampere rating in accrdance with the Natinal Electrical Cde, ANSI/NFPA Such vercurrent prtectin shall be prvided as a part f the heater unless it can be determined that equivalent vercurrent prtectin will be incrprated as a branch-circuit prtective device The requirement in 19.4 des nt apply t a mtr rated at 1/8 hrsepwer (93 W) r less cnnected t a circuit having vercurrent prtectin at 50 amperes r less.

41 APRIL 11,1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Ordinarily, a mtr having thermal prtectin that cmplies with the requirements fr such devices is acceptable with respect t the requirement in 19.4, if, in the equipment, it will be cnnected in series with a branch-circuit vercurrent-prtective device f the same type and having a current rating n mre than that with which the mtr-prtectr cmbinatin was tested during the investigatin f the prtectr Overcurrent prtectin at nt mre than 20 amperes shall be prvided by a circuit breaker r fuses, as a part f the equipment, fr each general-use duplex receptacle circuit, fr each transfrmer primary circuit (except as indicated in 19.9), and fr each lamphlder circuit independent f a heating element included in the heater, unless the equipment wuld be prperly cnnected in accrdance with the Natinal Electrical Cde, ANSljNFPA , t a branch circuit rated at 20 amperes r less Overcurrent prtectin at n mre than 15 amperes shall be prvided by a fuse r circuit breaker fr each general-use single receptacle, unless the equipment wuld be prperly cnnected in accrdance with the Natinal Electrical Cde, ANSljNFPA , t a branch circuit rated at 15 amperes r less The vercurrent prtectin may be mitted frm the primary f a Class 2 transfrmer, and may be mitted frm the primary f any ther transfrmer if there is n emissin f flame r mlten metal frm the heater enclsure when the transfrmer is perated under the cnditins described in and The transfrmer is t be perated cntinuusly at the test vltage indicated in Table 33.2 and at rated frequency with the enclsure grunded. Except as nted in 19.11, the lad cnnected t the utput terminals is t be a resistance f such value that three times the full-lad rated current will be drawn frm the secndary winding; and peratin is t be cntinued until cnstant temperatures are indicated by a thermcuple n the enclsure unless burnut ccurs earlier. The circuit n which the transfrmer is tested is t be prtected by fuses rated at n less than that required fr the heater The burnut test is t be cnducted with the utput terminals f the transfrmer shrt-circuited if such cnditin results in less than three times rated current being drawn frm the secndary. If the transfrmer cntrls a mtr and the mtr lcked rtr lad plus the additinal lad n the transfrmer is greater than three times the full-lad rated current, the test is t be cnducted with the utput terminals cnnected t the mtr with the rtr lcked, and the ther lads in parallel. If the transfrmer des nt cntrl a mtr, the lad impsed n the transfrmer by the cils f any slenids, relays, r the like, with the armature f the largest such device blcked pen is determined; and the test is t be cnducted with an equal resistance lad substituted fr the cils if this lad is greater than three times the full-lad rated current. If accessible fuses are prvided n the transfrmer, they are t be replaced with dummy fuses, but inaccessible fuses are t remain in the circuit A fusehlder r circuit breaker shall be f a type rated fr the particular applicatin and shall nt be accessible frm utside the enclsure withut pening a dr r cver, except that the perating handle f a circuit breaker may prject utside the enclsure. A plug fusehlder shall be s designed and installed that un insulated live parts ther then the screw shell will nt be expsed t cntact by persns remving r replacing fuses. 20 Thermal Cutffs 20.1 A thermal cutff shall be secured in place and s lcated that it will be accessible fr replacement withut damaging ther cnnectins r internal wiring. See A thermal cutff shall pen the circuit in the intended manner withut causing the shrt-circuiting f live parts and withut causing live parts t becme grunded t the enclsure when the heater is cnnected t a circuit having a vltage in accrdance with and perated in a nrmal psitin t cause abnrmal heating.

42 32 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, T determine if a thermal cutff cmplies with the requirement in 20.2, the heater is t be perated five times with separate cutffs as described abve, and with any ther thermally perated cntrl devices in the heater shrt-circuited. Each thermal cutff is required t perfrm acceptably. During the test, the enclsure is t be cnnected thrugh a 3-ampere fuse t grund. 21 Receptacles and Transfer Switches 21.1 Except as nted in 21.2, an attachment-plug receptacle fr general use prvided n a heater designed t be cnnected with ther similar units t frm a heating system shall nt be in electrical cnnectin with the heating-element supply terminals, that is, shall be supplied frm a separate circuit If a cmbinatin receptacle and transfer-switch accessry is prvided, the receptacle may be energized frm the heater branch-circuit prvided that the receptacle and the heater are nt cnnected simultaneusly t the same branch-circuit With reference t 21.2, the transfer-switch accessry shall be adequate fr cnnectin t the prper size branch-circuit t which the receptacle-switch cmbinatin is intended t be cnnected. See If a heater r accessry intended fr permanent cnnectin t the pwer supply cntains a plarized attachment-plug receptacle, the heater.r accessry shall be s wired that the receptacle cntact intended fr cnnectin t the grunded circuit cnductr is cnnected t an identified field-wiring terminal r lead Except as indicated in 21.6, in a receptacle accessry fr use in r with a permanently munted heater r heater system, either designed t be munted in the heater r supplied as a separately enclsed unit, the attachment-plug receptacle shall be prvided and shall be f the grunding type With reference t 21.5, the receptacle need nt be prvided under either f the fllwing cnditins, prvided the accessry is marked in accrdance with a) The receptacle need nt be prvided if the heater and accessry cmply with the requirements f and , bth with and withut the receptacle installed. b) The receptacle need nt be prvided if the penings fr installatin f the receptacle are clsed by knckuts. 22 Lamphlders 22.1 If a heater intended fr permanent cnnectin t the pwer supply r a heater equipped with a plarized attachment-plug cap is intended t be cnnected t the identified (grunded) cnductr f a pwer supply circuit, a lamphlder supplied as part f the heater shall be s wired that the screw shell will be cnnected t the identified cnductr Except as nted in 22.3, a lamphlder shall be s designed and installed that uninsulated live parts ther than the screw shell will nt be expsed t cntact by persns remving r replacing lamps in service The requirement in 22.2 des nt apply if, in rder t remve r replace a lamp, it is necessary t dismantle the heater by means f tls. See Switches 23.1 A switch r ther cntrl device shall have a current and vltage rating n less than that f the circuit Oad) which it cntrls.

43 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL A switch shall be s lcated r prtected that it will nt be subjected t physical damage in intended use. A thrugh-crd switch shall nt be prvided A switch shall be f the indicating type, r the switch functin, fr example, ON - OFF, HIGH - LOW, and the like, shall be therwise indicated with marking that is visible when the switch is made accessible A switching device that interrupts the main pwer-supply circuit t a fixed heater shall be such that, when pen, the device will discnnect all ungrunded cnductrs f the pwer-supply circuit if the switching device itself (r the pilt device that cntrls the switching device) has a marked "n" r "fr' psitin A switch r ther means f cntrl intended t permit the use f a limited number f elements at ne time shall be s lcated r f such a type that the cnnectins t permit the use f mre elements than intended are nt apparent A manually perable mtr-cntrl switch shall be prvided in a heater intended fr cnnectin t the pwer-supply circuit by flexible crd and an attachment-plug cap and emplying a mtr rated at mre than 1/3 hrsepwer (249 W). 24 Autmatic Cntrls and Cntrl Circuits General A cntrl circuit shall cmply with the requirements in If an auxiliary cntrl device (thermstat r cmbinatin thermstat and cntrl switch) in a fixed heater has a marked "fr' psitin, r anther wrding (such as "n heat," "cld," "0," r the like) that cnveys the same meaning as the wrd "ff," it shall discnnect the element r elements it cntrls frm all ungrunded cnductrs f the pwer-supply circuit when placed in that psitin (that is, when nt cycling) An auxiliary cntrl is cnsidered t be ne that is intended primarily fr such as time, temperature, r pressure regulatin under cnditins f intended peratin, and nt fr prtectin against verlad r excess temperature cnditins resulting frm abnrmal peratin A safety cntrl r a temperature-limiting cntrl (ne designed t prevent unsafe peratin f a heater) shall be perative whenever the heater is cnnected t its pwer supply. Operatin f such a cntrl shall interrupt pwer t a sufficient number f heating elements t reduce temperature t cmply with the requirements f A cmpnent such as a pilt light, capacitr, r resistr shall nt be cnnected acrss the cntact terminals f a safety cntrl r a temperature limiting cntrl A cntactr actuated by a limit cntrl shall cmply with the requirement fr a limit cntrl if it is a part f the limit-cntrl circqit A temperature-limiting cntrl fr use with basebard heaters shall nt functin during the Cntinuity f Operatin Test. See If a thermstat (r cmbinatin thermstat and cntrl switch) has a marked psitin as described in , it shall nt functin as a thermstat, that is, it shall nt respnd t temperature changes, while the actuating member is in that psitin.

44 34 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, The requirement in applies t a thermstat (r cmbinatin thermstat and cntrl switch) that is marked: a) With an "ff' psitin, r b) With anther wrding such as "n heat," "cld," "0," r the like that cnveys the same meaning as the wrd "ff." A thermstat that des nt reclse (remains pen) when cled t a temperature f minus 35 0 C (minus 31 F) is acceptable with respect t the requirements in Terminals and actuating members f safety devices The terminals f a safety device within the enclsure f a heater shall be s lcated r further enclsed that they will be prtected against accidental shrt-circuiting r damage The bulb, capillary tubing, r ther sensing element f a thermstat r limit switch that is depended upn t prevent hazardus peratin f the heater shall be s lcated r guarded as t be prtected frm physical damage during installatin and use f the heater In cnnectin with the requirement in , particular attentin is t be paid t a heater that, when being installed, requires partial disassembly r permits rearrangement f internal parts. 25 Spacings 25.1 Except as nted in 25.2 and 25.3, the spacings in a heater shall be in accrdance with Tables The spacings specified in Tables 25.1 and 25.2 d nt apply t the inherent spacings f a cmpnent part f a heater At clsed-in pints nly, such as the screw-and-washer cnstructin f an insulated terminal mqunted in metal, a spacing f 3/64 inch (1.2 mm) is acceptable in a heater rated at 250 vlts r less The spacings within a mtr cnnected acrss a prtin f a resistance element r in series with a reactr r an auttransfrmer shall be based n the full rated vltage f the heater Except as indicated in 25.6, an insulating lining r barrier f fiber r similar material emplyed where spacings wuld therwise be less than the required values shall be n less than 1/32 inch (0.8 mm) in thickness, and shall be s lcated r f such material that it will nt be adversely affected by arcing; except that fiber n less than 1/64 inch (0.4 mm) in thickness may be used in cnjunctin with an c;lir spacing f n less than 50 percent f the spacing required fr air alne Unless prtected frm physical abuse during assembly and the intended functining f the heater, a barrier f mica shall be 0.01 inch (0.25 mm) r mre in thickness.

45 APRIL 11,1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Table 25.1 Minimum acceptable spacings at field-wiring terminals and at fusehlders and thermal cutffsa,b Parts Invlved Ptential Thrugh air Over the surface Invlved, ~lts Inch (mm) Inch (mm) Between live metal parts f ppsite plarity; /4 ( 6.4) 3/8 ( 9.5) and between a live metal part and a dead metal part, ther than the enclsure, which may be /8 ( 9.5) 1/2 c (12.7}c grunded Between a live metal part and the enclsure /2 (12.7) 1/2 (12.7) ' a The spacings d nt apply t cnnecting straps r busses extending away frm wiring terminals, fusehlders r thermal cutffs. Such spacings are t be judged under Table b Applies t the sum f the spacings invlved where an islated dead part is interpsed. c A spacing f nt less than 3/8 inch (9.5 mm), thrugh air and ver the surface, is acceptable at wiring terminals in a wiring cmpartment r terminal bx if the cmpartment r bx is integral with a mtr. Table 25.2 Minimum acceptable spacings thrugh air r ver the surface at pints ther than field-wiring terminals, fusehlders, thermal cutffs, r inside mtr8 Ptential Invlved, Parts Invlved vlts Inch Between live metal parts f ppsite plarity; and /6 between a rigdly munted uninsulated live metal part and a dead metal part ther than the enclsure that either is /4 b,c expsed fr persns t cntact r may be grunded Between uninsulated live metal parts and the metal /4 enclsure (mm) b,c 6.4 a If an uninsulated live metal part is nt rigidly supprted, r if a mvable dead metal part is in prximity t an uninsulated live metal part, the cnstructin shall be such that at least the minimum acceptable spacing is maintained under all perating cnditins and under all nrmal cnditins f handling. b Enamel-insulated wire is cnsidered t be an uninsulated live. metal part. Hwever, a spacing f nt less than 3/32 inch r 2.4 mm (ver the surface and thrugh air) is acceptable between a dead metal part and enamel-insulated wire rigidly supprted and held in place n a mtr cil. c A spacing f 1/16 inch (1.6 mm) is permissible at the heating element nly in a heater rated fr 300 vlts r less.

46 36 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11,1994 Table 25.3 Minimum acceptable internal mtr spacings at ther than field-wiring terminals Ptential at the pints between which the Diameter f mtr spacings are measured, Parts frame, vlts Invlved Inches (mm) Thrugh air Inch (mm) Inch Over the surface (mm) Cmmutatr 7(17S) 1/16 (1.6) 1/16 r r less a clletr Mre than 1/S b (3.2)b 3/1S b rings 7(17S)a (1.6) (4.S)b Elsewhere 7(17S) 3/32 c (2.4)c 3/32 c in r less a the Mre than 1/S b,d (3.2)b,d 1/4 b,d mtr 7(17S)a (2.4)c (S.4)b,d 12S-250 Cmmutatr 7(17S) 1/1S (1.S) 1/1S r r less a cllectr Mre than 3/1S b (4.S)b 3/1S b rings 7(17S)a (1.S) (4.S)b Elsewhere 7(17S) 3/32 (2.4) 3/32 in r less a the Mre than 1/4 b,d (S.4)b,d 1/4 b,d mtr 7(17S)a (2.4) (S.4)b,d Cmmutatr r 7(17S) 1/4 e (6.4)e 1/4 cllectr rings r less a and live parts Mre than 1/4 (S.4) 3/S f the brush 7(17S)a rigging (S.4) (9.5) I i Elsewhere 7(17S) 1/4 d (S.4)d 1/4 d in r less a the Mre than 3/S d (9.5)d 3/S d mtr 7(17S)a (6.4)d (9.5)d a The frame diameter is the diameter, measured in the plane f the laminatins, f the circle circumscribing the statr frame, excluding lugs, bxes, r the like, used slely fr mtr munting, assembly r cnnectin. b Spacings f n less than 3/32 inch (2.4 mm) are acceptable thrughut a universal mtr. c Fr a mtr rated at 1/3 hrsepwer (249 W utput) r less, these spacings may be n less than 1/16 inch (1.S mm). d Enamel-insulated wire is cnsidered t be an uninsulated live part. Hwever, a spacing f nt less than 3/32 inch r 2.4 mm (ver the surface and thrugh air) is acceptable between enamel-insulated wire (rigidly supprted and held in place n a cil) and a dead metal part. e Spacings invlving a cllectr ring may be n less than 1/S inch (3.2 mm).

47 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Grunding 26.1 In a heater r accessry intended fr permanent cnnectin t the pwer-supply circuit, all expsed dead metal parts and all dead metal parts inside the enclsure that are expsed t cntact during any servicing peratin (including maintenance and repair) and that are subject t becming energized shall be electrically cnnected t the equipment-grunding terminal r lead Sectins f heaters and accessries intended t be intercnnected t frm a heating system supplied by a single branch circuit shall have prvisin fr maintaining cntinuity f a metal-t-metal grunding bnd between adjacent sectins On a prtable heater where grunding is prvided, whether required r nt, the pwer supply crd shall include a grunding cnductr which shall be: a) Green with r withut ne r mre yellw stripes, b) Cnnected t the grunding blade f an attachment-plug cap f a grunding type, c) Cnnected t the enclsure f the appliance by means f a screw nt subject t being remved during rdinary servicing, r by ther equivalent means. Slder alne is nt acceptable fr making this cnnectin (see als 26.5), and d) Bnded t all expsed dead metal parts and all dead metal parts expsed during any servicing peratin (including maintenance and repair) that are subject t becming energized A crd-cnnected heater rated mre than 150 vlts shall have prvisin fr grunding, in accrdance with With reference t 26.3 (c), a grunding cnnectin that is mechanically crimped befre being sldered is t be tested fr acceptability as a cnnectin withut the slder in place. 27 Guarding f Heating Elements 27.1 The heating element and any part f the element assembly such as an element supprt r sheath, shall be s guarded that flammable material as well as persns will be prtected against cntacting it The adequacy f a guard is judged with respect t its general serviceableness and with respect t the shape and/r size f the penings in it, in cnjunctin with the distance f the guard frm the heating element and the ther high-temperature parts mentined in Except as nted in 27.4, an pening in a guard is cnsidered t be acceptable if, with the heater in any intended perating psitin, the fllwing cnditins are met: a) The shape and size f an pening are such that a test gauge in the frm f a right-circular cne having a base diameter f 2-3/4 inches (70 mm) and an altitude f 5-1/2 inches (140 mm) is prevented frm tuching the heating element and the ther high-temperature parts mentined in 27.1 when the gauge is inserted, apex first, in any manner. See 27.3.

48 38 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, 1994 b) The shape and size f an pening which permits the vertically dwnward entrance f a bar 1/2 inch (12.7 mm) wide and 1/16 inch (1.6 mm) thick are such that a test gauge 1/16 inch in thickness and in the frm f an issceles triangle having a base f 2-3/4 inches (70 mm) and an altitude f 5-1/2 inches (140 mm) is prevented frm tuching the heating element and the ther hightemperature parts mentined in 27.1 when the gauge is inserted, apex first, in any manner. The testing f an pening with the triangle gauge applies als where the vertically dwnward insertin f the bar is prevented by the cnstructin f the guard and/r the use f an additinal barrier, unless the vertically applied bar tends t be deflected utward, that is, away frm the guard. c) The area f an pening in a substantially vertical face f a guard is n mre than 3-1/4 square inches (2100 mm 2 ) if the size and/r shape f the pening permits the entrance frm any hrizntal directin f a vertical rd 1/16 inch in diameter and 2-3/4 inches lng The fins f a metal-clad element are cnsidered t be element-guarding members, and need nt cmply with the prvisins in 27.2(a) if the temperature f the expsed edges (uter perimeter) f the fins is n mre than 280 C (536 F) under cnditins f cntinuus peratin Fr a heater f ther than the panel type in which the temperature f the heating element is n higher than 280 C (536 F) under cnditins f intended peratin, and fr a fan-type heater in which the fan is always in peratin when the heating element is "n" (energized) and the air current prevents clthing and the like frm entering the guard, penings in the guard are acceptable if they cmply nly with 27.2(a). Fr a panel-type heater in which the heating-element temperature is n higher than 280 C under cnditins f cntinuus peratin, 27.7 applies If a heater is required t have a guard, and if the guard is remvable, the heater and the guard shall be cntained in the same cartn as shipped frm the factry. See als A heater in which the heating element is designed fr intended peratin nly in an air current, shall be s wired r cntrlled that the element can be perated nly when under the cling effect f the air stream. A heater in which the cling effect f the mtin f a part is necessary t prevent excessive temperatures shall be s wired r cntrlled that the element cannt be perated withut such mtin Except as nted in 27.8, a panel-type heater shall be prvided with a guard that will prevent a test surface, in the frm f a 6-inch square (a square 150 mm n a side) parallel t the element panel, frm being brught clser than 1/2 inch (13 mm) t the plane f the frnt f the heater, excluding the guard The requirement in 27.7 des nt apply t a heater having an element panel perating at a temperature higher than 280 C (536 F) and required by 27.1 and 27.2 t have mre effective guarding A slt pening in the uter enclsure f a heater, if mre than 6 inches (150 mm) in length, shall be prvided with wire guards r the equivalent at intervals such that n sectin f the slt is uninterrupted fr a distance f mre than 6 inches (150 mm) unless the heater cmplies with the test requirement in An pening resulting frm intentinal manufacturing tlerances needed t permit assembly f enclsure parts des nt cnstitute a slt pening as mentined in If parts f the heating element assembly have sharp crners, edges, r prjectins, such parts shall be guarded in accrdance with the prvisins f 27.2(a), irrespective f the temperatures f the fins. See Exceptin: Parts f the heating element assembly which are s guarded that they cannt be tuched by the prbe illustrated in Figure 5.1 are cnsidered t be prtected against cntact.

49 ~ APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Flr Heaters 28.1 A flr-insert heater shall be s cnstructed t permit cleaning and t minimize the pssibility f the accumulatin f flammable dirt and Jitter where it might becme ignited A heater intended t be installed flush with r beneath a flr shall be prvided with an autmatic temperature cntrl ther than a thermal cutff. The cntrl shall cmply with the requirements in There shall be n penings in wiring cmpartments thrugh which bjects such as nails r pins may penetrate and cntact uninsulated Jive parts. PERFORMANCE 29 General 29.1 If a prtable heater is intended t be shipped with the legs detached r arranged in ther than the intended perating psitin, the tests are t be cnducted with the legs in place as well as detached r in the shipping psitin. See and nte (e) t Table Assembly instructins shall be furnished. See Exceptin: The tests with the legs detached r in the shipping psitin need nt be cnducted if. the heater is marked in accrdance with Pwer Input Test 30.1 The pwer input t a heater shall nt be mre than 105 percent f its marked rating Pwer input is t be measured with the heater at the intended perating temperature under full-lad cnditins and while cnnected t a supply circuit f rated vltage in accrdance with If a heater emplys a nnmetallic element (such as carbn), the pwer input is t be determined when the element is new. 31 Leakage Current Test 31.1 The leakage current f a crd-cnnected heater shall be nt mre than: a) 0.5 milliampere fr a heater having a nminal 120 vlt rating, and b) 0.75 milliampere fr a heater having a nminal 208 r 240 vlt rating Leakage current refers t all currents, including capacitively cupled currents, which may be cnveyed between expsed cnductive surfaces f a heater and grund r ther expsed cnductive surfaces f a heater All expsed cnductive surfaces are t be tested fr leakage currents. The leakage currents frm the surfaces are t be measured t the grund supply cnductr individually as well as cllectively where simultaneusly accessible and frm ne surface t anther where simultaneusly accessible. Parts are cnsidered t be expsed surfaces unless guarded by an enclsure cnsidered acceptable fr prtectin against risk f electric shck as defined in 4.13 and Accessibility f Uninsulated Live Parts, Film-Cated Wire, and Mving Parts, Sectin 4. Surfaces are cnsidered t be simultaneusly accessible where they can be cntacted by ne r bth hands f a persn at the same time. These measurements d nt apply t terminals perating at lw-vltages as defined by :'1. i.!

50 40 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, If a cnductive surface ther than metal is used fr the enclsure r part f the enclsure, the leakage current is t be measured using a metal fil with an area f 10 by 20 centimeters (4 by 8 inches) in cntact with the surface. Where the surface is less than 10 by 20 centimeters the metal fil is t be the same size as the surface. The metal fil is nt t remain in place lng enugh t affect the temperature f the heater The measurement circuit fr leakage current is t be as shwn in Figure The measurement instrument is defined in (a) - (d). The meter which is actually used fr a measurement need nly indicate the same numerical value fr a particular measurement as wuld the defined instrument. The meter used need nt have all the attributes f the defined instrument. a) The meter is t have an input impedance f 1500 hms resistive shunted by a capacitance f 0.15 micrfarad. b) The meter is t indicate 1.11 times the average f the full-wave rectified cmpsite wavefrm f vltage acrss the resistr r current thrugh the resistr. c) Over a frequency range f 0 t 100 kilhertz, the measurement circuitry is t have a frequency respnse (rati f indicated t actual value f current) equal t the rati f the impedance f a 1500 hm resistr shunted by 0.15 micrfarad capacitr t 1500 hms. At an indicatin f 0.5 r 0.75 milliampere, the measurement is t have errr f nt mre than 5 percent at 60 hertz. d) Unless the meter is being used t measure leakage frm ne part f a heater t anther, the meter is ~ be cnnected between the accessible parts and the grunded supply cnductr A sample f a heater is t be tested fr leakage current starting with the as-received cnditin with all switches and thermstats clsed, but with the grunding cnductr, if any, pened at the attachment plug. The as-received cnditin is withut prir energizatin, except as may ccur as part f the prductinline testing. Hwever, a crd-cnnected heater that cmplies with the Humidity Cnditining Test, Sectin 51, need nt be tested in the as-received cnditin, but instead may be tested after the cnditining specified in Sectin 51. The supply vltage is t be 120 r 240 vlts, depending upn the vltage rating f the heater. The test sequence, with reference t the measuring circuit, Figure 31.1, is t be as fllws: a) With switch S1 pened, the heater is t be cnnected t the measuring circuit. Leakage current is t be measured using bth psitins f switch S2. b) Switch S1 is then t be clsed, energizing the heater, and within a perid f 5 secnds, the leakage current is t be measured using bth psitins f switch $2 and with the heater perated at maximum heat setting f cntrls. c) Leakage current is t be mnitred until thermal stabilizatin under the maximum heat cnditin. Bth psitins f switch $2 are t be used. The equivalent f thermal stabilizatin is cnsidered t be attained as in the Cntinuus Operatin Test, and If any adjustable thermstat des nt cycle at the maximum heat setting, it is t be adjusted until it des cycle befre the final measurements at thermal stabilizatin are taken. Measurements are t be made with the thermstat, if any, pen and clsed. d) If the heater emplys a single ple switch r a cntrl thermstat fr adjusting temperatures, then mnitring f leakage current is t cntinue until the leakage current stabilizes r decreases after the heater is turned ff.

51 APRIL 11,1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Figure 31.1 Leakage-current measurement circuits T 120V L<::!--O--O' ' Sl S2 GR." INSULATING '--+-- TABLE LC100 GROUNDED SUPPLY CONDUCTOR B Prduct intended fr cnnectin t a 120 vlt pwer supply. T120V 240V <3----, L1< 2 0 0_V_-I--, LC200 Sl GROUNDED SUPPLY CONDUCTOR S2 PRODUCT METER GR B A.,----- "' INSULATING '-+-- TABLE Prduct intended fr cnnectin t a 240 r 208 vlt pwer supply. a) Prbe with shielded lead - under sme circumstances where higher frequ~ncy cmpnents are present, shielding f measuring instrument and its leads may be necessary. b) Separated and used as clip when measuring currents frm ne part f prduct t anther. 32 Cntinuity f Grunding Cnnectin Test 32.1 The resistance f the grunding path between all expsed dead metal parts and all dead metal parts expsed during any servicing peratin (including maintenance and repair) that are liable t be energized, and the equipment-grunding terminal r lead r the pint f attachment f the wiring system r the grunding blade f an attachment plug, shall be n mre than 0.1 hm.

52 42 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, The resistance may be determined by any cnvenient methd except that when referee measurements are necessary, either a direct r alternating current at a ptential f n mre than 12 vlts, and equal t the maximum current rating f the branch-circuit vercurrent prtectin device that may be emplyed with the heater is t be passed frm the equipment grunding terminal r the pint f attachment f the wiring system r the grunded blade f the attachment plug t the dead metal part, and the resulting drp in ptential in vlts divided by the current in amperes passing between the tw pints is t be calculated t btain the resistance. 33 Temperature Test 33.1 General An autmatic temperature-regulating cntrl is t be shunted ut f the circuit during all Cntinuus Operatin and Abnrmal Operatin Tests. If its peratin is s affected by the temperature f the external ambient air that a hazardus cnditin may result, a temperature-limiting cntrl is als t be shunted ut f the circuit unless the heater is subjected t the tests specified in The temperature-limiting cntrl need nt be shunted ut f the circuit if all f the Abnrmal Operatin Test (vervltage, tip ver, drape, stalled fan, cheeseclth drape, padded surface and blanketing usually perfrmed n the heater) are repeated while the heater is lcated in a rm having an average temperature f OOC (32 F) Fr bth Cntinuus Operatin and Abnrmal Operatin Tests, a prtable heater and sectins f fixed heaters are t be munted in the intended manner in a wall angle as described in The sectins are t be installed as clse t the flr as their cnstructin will permit unless they are marked in accrdance with The test installatin f a basebard-type heater system is t emply at least three heater sectins and ne r mre accessry sectin, unit, r fitting intended fr use with the system, such as receptacle, thermstat, r crner sectins. An accessry sectin is t be cnnected between tw heater sectins. If an inside crner sectin is supplied, it is t cnnect tw heater sectins as intended The felt mentined in and 41.2 is t be 100-percent standard-weight, all-cattle-hair, punched felt with center reinfrcement cnsisting f burlap having a mass f 5 unces per square yard (170 g/m 2 ). Felt 1 inch (25 mm) thick has a mass f 105 ± 15 unces per square yard (3.56 ± 0.51 kg/m2). Felt 3/4 inch (19 mm) thick has a mass f 79±9 unces per square yard (2.68±0.31 kg/m 2 ) Wherever cheeseclth is mentined in cnnectin with either a Nrmal- r an Abnrmal Temperature Test, the clth is t be bleached cheeseclth 36 inches (910 mm) wide, running yards per pund (apprximately m/kg), and having what is knwn t the trade as a "cunt f 32 x 28," that is, fr any square inch, 32 threads in ne directin and 28 threads in the ther directin (fr any square centimeter, 13 threads in ne directin and 11 threads in the ther directin) The blanket material mentined in 41.3 is 100 percent unbleached cttn flannelette sheet blanket, and is generally available in the 80-by-l08-inch (2-by-2.7-m) size The white duck material mentined in 42.2 is t have a mass f 8 unces per square yard (0.27 kg/m 2 ).

53 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL A heater is t be munted r placed in the intended manner n r against the black-painted surface f a wall cnsisting f 3/8 inch (9.5 mm) thick plywd fastened t bth shrter sides f trade size "2 x 4" (38 x 89 mm) vertical wden studs n 16-inch (405-mm) centers. Tw r mre such walls are t be fastened tgether t frm a 90-degree angle, and the height and length f the walls are t be such that they extend nt less than 2 feet (610 mm) beynd the physical limits f the heater, see The heater is t be lcated as clse t the sides f the wall angle as its cnstructin will perrnit, and it is t be s placed relative t the walls that maximum heating will ccur n the latter In additin, an individual wall-insert heater is t be munted in a bx-like structure f 3/8-inch (9.5- mm) plywd r the equivalent with the internal dimensins such that the walls make a clse fit with the heater shell n the fur sides and rear (but the walls f the bx are t be perpendicular t its back) and having a flat frnt surface simulating the wall surface in which the heater is designed t be munted; The assembly f the heater and the plywd bx is t be munted in an apprpriate pening in the wall mentined in The depth f the wall is t be increased if necessary t accmmdate the heater and bx-like structure Unless it has been determined that it will remain in psitin during the handling f the heater prir t and during installatin and after the heater has been installed, external thermal insulatin, such as mats f wven glass fiber r mineral wl, is t be remved frm the heater befre it is installed in r n the surfaces f the test enclsure Rubber r ther material similarly subject t deteriratin is t be remved frm feet r ther supprts f a prtable heater if the remval f the material is liable t result in higher temperatures. being attained n the heater If the remval f feet r ther supprts results in peratin f prtective devices during the Cntinuus Operatin Test, such peratin is nt cnsidered t be unacceptable if, when the test is repeated with the parts replaced in the intended manner, there is n peratin f the prtective devices T simulate carpeting, 3/ 4-inch (19-mm) thick felt pads are t be used and are t be lcated as specified in A heater shall be tested under the applicable cnditins in accrdance with and the fllwing: a) If carpeting r equivalent material can be laid flat n the flr within its lwer pening, the heater shall be tested with such materials s placed and pushed as far back as the cnstructin will permit. b) If guards r ther design features prevent carpeting r equivalent material frm being laid flat n the flr within the lwer pening f the heater, the test shall be made with such material as clse t the heater as the heater cnstructin will permit. c) If marked in accrdance with 54.30, a fixed heater shall be munted with its lwer edge f the specified distance abve the flr, and the test shall be made with carpeting r equivalent material placed clse t the wall belw the heater. I I '"j

54 44 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, Temperatures are t be measured by thermcuples cnsisting f wires n larger than N. 24 AWG (0.21 mm 2 ) and n smaller than N. 30 AWG (0.05 mm 2 ) except that a cil temperature may be determined by the change-f-resistance methd if the cil is inaccessible fr munting thermcuples (see ). When thermcuples are used in determining temperatures in electrical equipment, it is standard practice t emply thermcuples cnsisting f N. 30 AWG (0.05 mm 2 ) irn and cnstantan wire and a ptentimeter:type instrument; and such equipment is t be used whenever referee temperature measurements by thermcuples are necessary A temperature is cnsidered t be cnstant when three successive readings, taken at intervals f 10 percent f the previusly elapsed duratin f the test (but n less than 5-minute intervals), indicate n change. The thermcuple wire is t cnfrm with the requirements fr "special" thermcuples as listed in the table f limits f errr f thermcuples in the Standard fr Temperature-Measurement Thermcuples, ANSI MC A thermcuple junctin and adjacent thermcuple lead wire are t be held in thermal cntact with the surface f the material whse temperature is being measured. In mst cases, thermal cntact will result frm taping r cementing the thermcuple in place but, if a metal surface is invlved, brazing, r sldering the thermcuple t the metal may be necessary Ordinarily a thermcuple is t be used fr determining temperature f a cil r winding if it can be munted, withut remval f encapsulating cmpund r the like: a) On the integrally applied insulatin f a cil withut a wrap, r b) On the uter surface f a wrap that is n mre than 1 /32 inch (0.8 mm) thick and cnsists f cttn, paper, rayn, r the like (but nt f asbests r similar thermal insulatin). The change-f-resistance methd is t be used if the thermcuple measurement cannt be cnducted in accrdance with the freging cnsideratins. Fr a thermcuple-measured temperature f a mtr cil, the thermcuple is t be munted n the integrally applied insulatin n the cnductr At a pint n the surface f a cil where the temperature is affected by an external surce f heat, the temperature rise measured by means f a thermcuple may be higher by the fllwing amunt than the maximum indicated in Table 33.1, if the temperature rise f the cil measured by the resistance methd is n greater than specified in Table Item In Table 33.1 Additinal thermcuple rise, degree C (F) A.1.a 5 (9) A.2.a and B.1.a 15 (27) A.3.a 10 (18) A.4.a 20 (36) T determine if a heater cmplies with these requirements, it is t be perated cntinuusly until cnstant temperatures have been reached. The test vltage is t be as indicated in Table 33.2, except that if the applicatin f the indicated test vltage des nt result in the measured wattage input t the heater being equal t r mre than the marked rating, the test vltage is t be increased until the measured wattage input equals the marked rating.

55 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL I I Table 33.1 Maximum temperature rises I I Degrees A. a Mtr Materials and cmpnents C F 1. Class A insulatin systems n cil windings f alternating-current mtrs 7 inches (178 mm) r less in diameter (nt including universal mtrs). a. In pen mtrs; Thermcuple r resistance methd b. In ttally enclsed mtrs; Thermcuple r resistance methd Class A insulatin systems n cil windings f alternating-current mtrs mre than 7 inches (178 mm) in diameter and f direct-current and universal mtrs: a. In pen mtrs; Thermcuple methd Resistance methd b. In ttally enclsed mtrs; ': ~;,>.:,I': ' Thermcuple methd Resistance methd 3. Class B insulatin systems n cil windings f alternating-current mtrs 7 inches (178 mm) r less in diameter (nt including universal mtrs): a. In pen mtrs; Thermcuple r resistance methd b. In ttally enclsed mtrs; Thermcuple r resistance methd Class B insulatin systems n cil windings f alternating-current mtrs mre than 7 inches (178 mm) in diameter and f direct-current and universal mtrs: a. In pen mtrs; Thermcuple Resistance methd b. In ttally enclsed mtrs; Thermcuple Resistance methd B. Cmpnents 1. Relay, slenid, transfrmer, and ther cils with: a. Class 105 insulatin system; Thermcuple methd Resistance methd (Cntinued)

56 46 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, 1994 Table 33.1 Maximum temperature rises (Cnt'd) b. Class 130 insulatin system; Degrees Materials and cmpnents C F Thermcuple methd Resistance methd c. Class 155 insulatin system: Class 2 transfrmers; Thermcuple methd Resistance methd Pwer transfrmer; Thermcuple methd Resistance methd d. Class 180 insulatin system: Class 2 transfrmer; Thermcuple methd Resistance methd Pwer transfrmer; Thermcuple methd Resistance methd Other cmpnents and materials: a. Fiber used as electrical insulatin r required bushings b. Varnished clth insulatin c. Thermplastic material 25 C (77 F) less than its temperature rating d. Phenlic cmpsitin used as electrical insulatin r as partt where failure will result in nn-cmpliance with the ther requirements in this standard e. Wd r ther cmbustibles f. Sealing cmpunds 40 C (770F) less than the melting pint g. Fuses 65 /117 C.CONDUCTORS 1. Aexible crd and wire 25 C (77 F) less than its temperature rating C 2. Cpper cnductr, bare r insulated withut tinning, nickel cating, r silver plating, except as nted in item Terminatin f cpper cnductr in a pressure terminal cnnectr, unless bth are tinned, nickel-cated, r silver-plated D. GENERAL 1. Any pint n a surface adjacent t a permanently cnnected prduct r t a crd-cnnected heater Qncluding the surface n which it is munted), specified pints n test surfaces and enclsures at designated clearances frm the prduct, a metal surface f the prduct at the pint f cntact with the test surface, and the exterir surface f a recessed prduct that may cme int cntact with cmbustible material within the test enclsure (Cntinued)

57 r APRIL 11,1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Table 33.1 Maximum temperature rises (Cnt'd) Materials and cmpnents 2. Any pint within a terminal bx r wiring cmpartment f a permanently cnnected appliance in which field-installed cnductrs are t be cnnected, including such cnductrs themselves, unless the appliance is marked in accrdance with Register temperatures flr insert heater: a. Metallic grille b. Nnmetallic grille 4. Knbs and handles, r buttns likely t be cntacted by the user during nrmal peratin, and the surfaces likely t be cntacted by hands r fingers in grasping handles r buttnsd,e a. Metal b. Nnmetallic f 5. All expsed exterir surfaces f heaters which are nt defined by (3) and (4 e,g) C Degrees a The mtr diameter is t be measured in the plane f the laminatins f the circle circumscribing the statr frame, excluding lugs, bxes, and the like, used slely fr mtr COOling, munting, assembly, r cnnectin F b The limitatins n phenolic cmpsitin d nt apply t cmpunds which have been investigated and fund t have special heat-resistant prperties. c Inside a prduct, the temperature rise n a wire r crd may be greater than the specified maximum rise prvided that the insulatin n each individual cnductr is adequately prtected by supplementary insulatin (such as a braid, wrap, tape, r clse-fitting tubing) which is entirely suitable fr the temperature and type f insulatin invlved. d Pints likely t be cntacted by a hand r fingers include thse points n the gripping surface and adjacent surfaces clse enugh t be tuched while supprting the heater in the nrmal intended manner. The length f a nrmal gripping surface is t be cnsidered 4 inches (102 mm). Pints n a surface are nt t be cnsidered likely t be cntacted if prtected by a barrier nt less than 5/8 inch (15.9 mm) wide n which the temperature rise des nt exceed the value indicated in (04) r if a thrugh air spacing f nt less than 1-1/2 inches (38 mm) at the index finger is prvided frm the gripping surface t the ht part. e Fr prtable heaters which are shipped with the legs detached, these temperature limitatins are applicable nly when the heater is perated with the legs in place. See f A knb, handle, r buttn made f nnmetallic material which is plated r clad with metal having a thickness f inch (0.13 mm) r less is cnsidered t be and is judged as a nnmetallic part. g Expsed exterir surfaces f heaters are t be defined as the surfaces making cntact with a circular disc gage 8 inches (203 mm) in diameter and 1/16 inch (1.6 mm) thick when the gage is rlled arund the cntur f the heater, perpendicular t the hrizntal axis f the heater. This determinatin is t be made with the heater unmunted, but is t exclude thse surfaces in cntact with the intended munting surfaces f the heater. Exceptin: On heaters which are marked as indicated in 54.2, this temperature limit des nt apply within 1 inch (25.4 mm) as measured ver surface frm the utermst edge f any pening thrugh which heated air passes. The utermst edge f such an pening is cnsidered t be the lcatin clsest t the pening cntacted by the disc gage, and the 1 inch (25.4 mm) is t be measured in a directin away frm the pening. See Rgure

58 48 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, 1994 Table 33.2 Vltage fr temperature testa Marked vltage rating Value within ne f the specified ranges Test ptential In vlts Highest value f crrespnding specified ranges Value nt within ne f the specified ranges Rated Vltage a "Specified range" refers t any f the ranges f vltage mentined in Figure 33.1 Typical utlet air penings - utermst edges" indicated by "E" E E ~ DISC GAGE '.../ - -- "'" <~)~)~),,,, ) ) ) ~ ( ( ( ( I I I I I I I I,~E)j ijj U~E, <,... -::1 <,---, < -- -', -07 lj - \' !J-\, \ \, ) ) ) ( ( ( I I I I I I I I I ~!! ~E i77222 ~ / / ECS20 «,,-,\,,- \ \ "'" ~, \ _/ - -';--.l; -=77ZZ22222& I I ( ( I I I I I I

59 r APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL If a heater emplys a mtr in additin t a heating element, the vltage applied t an integrally cnnected mtr is t be the marked vltage rating f the heater, in accrdance with A mtr supplied frm a separate circuit is t be perated at a vltage (depending upn the mtr rating) as specified fr an integrally cnnected mtr In cnducting a test t determine if a heater cmplies with the temperature requirements, it is t be munted r supprted as in service and tested under cnditins apprximating thse f nrmal peratin, except as therwise nted. Temperatures are t be taken n nearby surfaces, n the supprting surface, at pints f supprt, n attachment plugs, and at ther pints as may be necessary, including building wiring that may be lcated adjacent t r behind a permanently installed heater Temperatures n the register f flr insert heaters are t be btained after equilibrium utlet air temperatures are attained. Surfaces f the register, in an essentially hrizntal plane, and likely t be cntacted by a persn walking r falling upn the grille are then t be explred with a surface pyrmeter t determine the single pint attaining the highest temperature rise. The thermcuple is then t be attached at this pint and this temperature is t be recrded until an equilibrium temperature cnditin is attained. See (0.3) f Table 33.1 fr the applicatin temperature rise limit Cntinuity f peratin test The limit cntrl f a heater shall nt functin when the heater is perated under the cnditins f the Cntinuus Operatin Test, in a rm ambient temperature f 25 ± 2 C (77 ± 3.6 F) except that the rm ambient temperature may be higher if the cntrl des nt functin Cntinuus peratin test Basebard heating equipment shall nt attain a temperature at any pint as t cnstitute a risk f fire r t damage any material emplyed in the heater, nr shw temperature rises at specific pints greater than thse indicated in Table All values in Table 33.1 are based n an assumed ambient (rm) temperature f 25 C (77 F), but a test may be cnducted at any ambient temperature within the range f C ( F). 34 Abnrmal Operatin Test 34.1 The applied vltage and methd f munting shall be.in accrdance with , during all Abnrmal Operatin Tests. In mst cases, cntinuus peratin fr 7 t 8 hurs will be necessary in rder t make sure that the ultimate results have been bserved When perated under such abnrmal cnditins, a heater is cnsidered t invlve a risk f fire if any f the temperatures measured n the flammable material exceed the maximum limits indicated in 34.3, if there is any emissin f flame r mlten metal, r if there is glwing r flaming f the flammable material upn which the heater is placed r, in the case f a permanently installed heater, f flammable material that is in prximity t the device as installed During the abnrmal tests cvered by Sectins 38, 39, 41, and 42, the temperatures f the cheeseclth r blanket material shall nt exceed 175 C (347 F), except that during the initial 5 cycles f peratin f the limit cntrl r 2 hurs, whichever cmes first, a temperature f 200 C (392 F) is permitted. The temperature f the cheeseclth is t be measured by thermcuples lcated between the layers f the cheeseclth, and the temperature f the blanket is t be measured by thermcuples lcated between the tw layers f blanket clsest t the heater.

60 50 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, After having been subjected t an abnrmal test, a crd-cnnected heater is cnsidered t invlve a risk f electric shck if: a) It appears t be useable, and b) The insulatin resistance is less than 50,000 hms If a mtr is cnnected acrss a prtin f a resistance element, the heater shall nt create a risk f fire and shall emit neither flame nr mlten metal as the result f an pen circuit in that prtin f the element that is in parallel with the mtr. 35 Overvltage Test 35.1 A heater shall be capable f perating fr 2 hurs withut creating a risk f fire, while cnnected t a supply circuit f the intended capacity and having a ptential 12 percent mre than the rated vltage f the heater The heater is t be perated at a vltage in accrdance with until cnstant temperatures are attained, fllwing which it is t be perated fr 2 hurs at a 12 percent higher vltage. 36 Mtr Switch Overlad 36.1 A switch r ther device that cntrls a mtr, unless s interlcked that it will never have t break the lcked-rtr mtr current, shall perfrm acceptably when subjected t an verlad test cnsisting f 50 cycles f peratin, making and breaking the lcked-rtr current f the mtr A switch r ther cntrl device is t be cnnected t a grunded supply circuit f rated frequency and f vltage in accrdance with , with the rtr f the mtr lcked. During the test, expsed dead metal parts f the heater are t be cnnected t grund thrugh a 3-ampere fuse, and the current-rupturing device, if single-ple, is t be lcated in an ungrunded cnductr f the supply circuit. If the heater is intended fr use n direct current, r n direct current as well as alternating current, the test is t be cnducted with direct current and expsed dead metal parts are t be s cnnected as t be psitive with respect t a single-ple, current-rupturing device. The device is t be perated at the rate f 10 cycles per minute, except that a faster rate f peratin may be emplyed if agreeable t all cncerned. The perfrmance is unacceptable if the fuse in the grunding cnnectin is blwn during the test The switch r device shall be mechanically and electrically perable at the cnclusin f the test, at which time the device shall be capable f perfrming its intended functin and shall shw n wear, lsening f parts, r defects f any ther descriptin which will diminish the reliability f the device. 37 Stability Test 37.1 A prtable heater shall return t its intended at-rest psitin n a level surface after being subjected t the fllwing separate cnditins: a) Tipped in any directin t an angle f 10 degrees frm hrizntal, and b) Subjected t a frce f 4 punds (17.8 N) r 25 percent f the weight f the heater, whichever is less, externally applied in a hrizntal directin t the pint n the heater prviding the greatest tendency t verturn it.

61 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL The tests are t be cnducted n the units when placed under the mst unfavrable cnditins. The heater shall be arranged with all drs and ther appurtenances in the psitin tending t decrease stability. The legs r ther pints f supprt may be blcked t prevent the unit frm sliding during the applicatin f the externally applied frce. 38 Tip Over Test 38.1 A crd-cnnected heater verturned in any psitin n a sftwd surface cvered with a duble layer f cheeseclth, shall nt cause the clth r wd t glw r flame A heater is t be perated under the mst severe cnditins that wuld result when it cmes t rest, withut further guiding r prpping, after having been pushed ver. The heater is t be perated as in the Cntinuus Operatin Test until the temperatures stabilize befre being tipped ver. See als Cheeseclth Drape Test 39.1 A heater cvered with a duble layer f cheeseclth shall nt cause the clth t glw r flame The entire length f the heater is t be initially cvered and the lwer end f the cheeseclth is t be arranged t cnfrm as clsely as pssible with the cntur f the heater, see Figures 39.1 and The heater shall be at apprximately rm ambient temperature at the start f this test. The test is t be repeated by perating the heater until cnstant temperatures are attained befre cvering it with the duble layer f cheeseclth. The temperature limitatins specified in 34.3 are nt applicable during thi~ rel!>eated prtin f the test In a test t determine whether r nt a cmbinatin heater and mtr-drive fan cmplies with the requirement in 39.1 the fan is t be perated when the heater is cvered with cheeseclth.. Figure 39.1 Cheeseclth drape CHEESECLOTH HEATER S2741

62 52 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, 1994 Figure 39.2 Cheeseclth drape CHEESECLOTH HEATER S Stalled Fan Test 40.1 A cmbinatin heater and mtr-driven fan shall nt create a risk f fire and shall emit neither mlten metal (excepting melted slder) nr flame with the fan mtr stalled and withut any cheeseclth cvering the appliance. 41 Padded Surface and Blanketing Test 41.1 When tested in accrdance with 41.2 and 41.3, a heater shall nt cause the cheeseclth, felt, blanket material, r wd t glw r flame. The heater shall be at apprximately rm ambient temperature at the start f the Padded Surface Tests and at the start f the Blanketing Tests. See als 34.4.

63 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Figure 41.1 Test f basebard - type heater 41.2 A wd surface cvered with a 1 inch (25 mm) thick felt pad, and with the pad, in turn, cvered by a duble layer f cheeseclth, is t be supprted in a vertical psitin as near the heater as the cnstructin f the latter will permit. The heater sectins are t be cvered t such an extent as t prduce maximum heating f the cheeseclth, and the padded surface is t extend at least 3 inches (76 mm) abve the tp surface f the heater. During the test, the cvered wd surface is t be mved hrizntally 1/2 inch (13 mm) away frm its initial psitin and peratin cntinued until temperatures stabilize. If it is determined that its temperature increases when the surface is mved hrizntally, the test is t be repeated with the surface in the new psitin starting with the heater at apprximately rm ambient temperature. The wd surface is t be f sufficiently rigid cnstructin s that it will nt change shape (bw r warp) during the test With the padded vertical surface in its initial psitin in frnt f the heater, fur thicknesses f lsely flded cttn blanket material are t be intrduced int the space between the vertical padded surface and the vertical wall n which the heater is munted in such a manner that the upper slt f the heater is blcked. The flded blanket material is t be lcated at any pints alng the length f the heater installatin in such a manner that any sensing device prvided is s expsed as t prduce the mst adverse perating cnditins. A length f flded material up t a maximum f 80 inches (2 m) is t be used, but a shrter length f the material may be intrduced int the space at anyne time (see Figure 41.1) t btain the mst adverse perating cnditins pssible. Operatin in anyne blcked cnditin is t be cntinued until cnstant temperatures are btained, r until glwing r flaming f the cttn blanket material results. 42 Curtain Drape Test 42.1 A heater shall nt cause a curtain draped in frnt f it t glw r flame. See als 34.4.

64 54 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, The upper edge f a simulated curtain at least 3 feet (0.9 m) high, but lng enugh t be supprted at least 1 ft (300 mm) abve the heater in any case, is t be cntinuusly attached t the wall at the base f which the heater is installed. The curtain is t cnsist f white duck as specified in and an verlay f a duble layer f cheeseclth n the side facing the heater, and is t be hung s that the lwer edge just tuches the flr. During the test, the entire length f the heater is t be initially cvered and the curtain is t be arranged t cnfrm as clsely as pssible with the cntur f the heater. See Figures 42.1 and Thse sectins judged t be least likely t affect the peratin f the limit cntrl are t be cvered. This test shall then be repeated with first: a) 3/4 f the heater cvered, then with b) 1/2 f the heater cvered, and then with c) 1/4 f the heater cvered. Each test shall be cnducted with the heater at rm ambient at the start f the test. Figure 42.1 Curtain drape CURTAIN HEATER S2743

65 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Figure 42.2 Curtain drape S Shredded Paper Test 43.1 If the guard described in 26.9 is nt prvided, there shall be n glwing r flaming f dry, shredded newspaper while a heater is in peratin under therwise intended cnditins. The newspaper is t be intrduced in any quantity and psitin in the pen slts t attain the mst adverse perating cnditins A flr insert heater is t be perated as described in , , , , and Tw sheets f newspaper having face dimensins equal t the grille f the heater are t be shredded int strips and the strips are then t be slwly (ver a perid f 5 minutes) inserted thrugh the heater's grille. There shall be n glwing r flaming f the dry, shredded paper while the heater is perated fr 7 hurs r until the ultimate results have been bserved. 44 Hydr-Static Pressure Test 44.1 Except as nted in 44.2, a part that is subject t air r vapr pressure (including the vapr pressure in a vessel cntaining nly a superheated fluid) during intended r abnrmal peratin shall withstand withut failure a pressure equal t the highest f the fllwing that is applicable: a) Five times the pressure crrespnding t the maximum setting f a pressure-reducing valve prvided as part f the assembly, but n mre than five times the marked maximum supply pressure frm an external surce and n mre than five times the pressure setting f a pressurerelief device prvided as part f the assembly. b) Five times the marked maximum supply pressure frm an external surce, except as prvided in (a). c) Five times the pressure setting f a pressure relief device prvided as part f the assembly. d) Five times the wrking pressure marked n the part, if s marked. e) Five times the maximum pressure develped within the part during any f the applicable peratin tests cvered by this standard.

66 56 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, A test need nt be perfrmed t determine whether r nt a part cmplies with the requirement in 44.1, if study and analysis indicate that the strength f the part is adequate fr the purpse as a result f its material and dimensins, fr example, cpper r steel pipe f standard size prvided with standard fittings If a test is necessary t determine if a part cmplies with the requirement in 44.1, tw samples f the part are t be subjected t a hydrstatic-pressure test. Each sample is t be s filled with water as t exclude air and is t be cnnected t a hydraulic pump. The pressure is t be raised gradually t the specified test value, and is t be held at that value fr 1 minute. The results are nt acceptable if either sample bursts r leaks, except as indicated in Leakage at a gasket during the hydrstatic-pressure test is nt cnsidered t cnstitute failure unless it ccurs at a pressure 40 percent r less f the required test value. 45 Static Lad Test 45.1 The register f a flr-insert heater shall withstand a static lad f 300 punds (660 kg) applied t a surface area f 1 square ft (0.093 m 2 ) at the center f the register withut any permanent deflectin and withut distrtin f the register supprt. 46 Water Splash Test 46.1 There shall be n dielectric failure in a flr insert heater as a result f splashing with water and the insulatin resistance shall be at least 50,000 hms A cttn mp, which has been cmpletely immersed in a pail f water fr at least 5 minutes, is t be immediately upn remval frm the pail swabbed acrss the heater's grille five times with the heater initially energized. Immediately fllwing a last swabbing peratin, the insulatin resistance measurement and Dielectric Vltage Withstand Tests are t be perfrmed. 47 Impact Test 47.1 A panel f glass r similarly brittle material emplyed in a heater shall withstand, withut cracking r breaking, the impact resulting frm the test described in Figure A panel f glass r similarly brittle material emplyed in a heater shall withstand, withut cracking r breaking, while in a fully heated cnditin, the applicatin f: a) A wet clth, fully saturated with water at rm temperature, wiped acrss the surface f the panel; and b) After the panel has returned t nrmal perating temperature, a fine spray f water played acrss the surface f the panel.

67 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL Figure 47.1 Impact test / suspensin pint suspending wire r crd f / any cnvenient length / steel sphere ~panel (edgewise view) IP Strain Relief Test 48.1 When tested in accrdance with 48.2, the strain-relief means prvided n the flexible crd shall withstand fr 1 minute, withut displacement, a direct pull f 35 punds frce (156 N) applied t the crd, with the cnnectins within the heater discnnected The frce specified in 48.1 is t be applied t the crd and supprted by the heater s that the strainrelief means will be stressed frm any angle that the cnstructin f the heater permits. The strain relief is nt acceptable if, at the pint f discnnectin f the cnductrs, there is sufficient mvement f the crd t indicate the stress n the cnnectins wuld have resulted. 49 Burnut Test (Slid-State Cmpnents) 49.1 If a heater emplys ne r mre rectifiers, transistrs, r similar slid-state cmpnents, n hazardus cnditin shall develp when the circuit between any tw terminals f any such cmpnent is pen-circuited r shrt-circuited. If the heater emplys a capacitr in cmbinatin with ne r mre f the abve-mentined cmpnents, n hazardus cnditin shall develp when the capacitr is shrt-circuited. Only ne f the simulated fault cnditins described abve is t be impsed at ne time. See

68 58 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, If an electrn-tube rectifier is emplyed, all f its plate and cathde terminals are t be cnnected tgether. The test is t be repeated with nly the cathde and heater terminals cnnected tgether if this cnditin was nt represented by the first test If a semicnductr rectifier is emplyed, three samples are t be tested with the rectifier terminals cnnected tgether. Three additinal samples are t be tested with the terminals f the electrlytic capacitr cnnected tgether Three cmplete tests are t be made under each f the cnditins described in 49.2 and 49.3, using new cmpnents in each test An unacceptable cnditin is cnsidered t exist if flame is emitted frm the verall enclsure f the equipment r if a permanently cnductive path is established between live parts and expsed dead metal The test described in may be mitted if ne r bth f the fllwing cnditins exist: a) There is 10,000 hms r mre additinal series impedance in a circuit in which the vltage is 125 r less. b) There is 20,000 hms r mre additinal series impedance in a circuit in which the vltage is mre than 125 but is n mre than Dielectric Vltage Withstand Test 50.1 A heater r electrical accessry shall withstand fr 1 minute withut breakdwn the applicatin f a 60 hertz essentially sinusidal ptential between live parts and dead metal parts, with the heater at its maximum nrmal perating temperature. The test ptential shall be 1000 vlts fr a heater rated at 250 vlts r less, and 1000 vlts plus twice rated vltage fr a heater rated at mre than 250 vlts A transfrmer, the utput vltage f which is essentially sinusidal, can be varied and can maintain the specified high ptential vltage at the equipment during the duratin f the test, is t be used t determine cmpliance with the freging. The applied ptential is t be increased gradually frm zer until the required test value is reached, and is t be held at that value fr 1 minute. 51 Humidity Cnditining Test 51.1 The requirements in Sectin 51 pertain t a heater emplying: a) Thermal insulatin such as mineral wl in cntact with an uninsulated live part, r b) insulating material, such as magnesium xide, that may be adversely affected by misture under cnditins f intended use Fllwing the cnditining specified in 51.3, a heater: a) Having a nminal vltage rating f 240 vlts r less, shall cmply with the requirements fr leakage current in 31.1 when tested as described in b) Having a nminal vltage rating abve 240 vlts, shall have an insulatin resistance, determined as specified in 51.5, f nt less than 50,000 hms between live parts and intercnnected dead metal parts.

69 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL A sample f a heater is t be heated t a temperature just abve 34 C (93 F) t reduce the likelihd f cndensatin f misture during cnditining. The heated sample is t be placed fr 48 hurs in a humidity chamber having air with a relative humidity f 88 ± 2 percent at a temperature f 32 ± 2 C (90 ±4 F) Leakage current is t be determined as described in 31.6(a), (b), and (c), except that a heater intended fr permanent cnnectin t a 120-vlt pwer supply is t be tested with switch S2 f Figure 31.1 nly in the psitin that crrespnds t the intended field supply cnnectin. The test is t be discntinued when the leakage current stabilizes r decreases Insulatin resistance is t be determined as fllws (see Figure 51.1) r by anther methd that is equally accurate. A direct current ptential f apprximately 250 vlts is t be applied between live parts and intercnnected dead metal parts. Tw vltmeters are t be used; ne vltmeter is t be cnnected acrss the supply line and the ther cnnected in series with ne f the leads t the heater being tested. With the supply vltage adjusted s that the difference in the vltage readings f the tw meters is apprximately 250 vlts, the insulatin resistance is t be calculated using the equatin: Insulatin Resistance = (J in which: V 1 is the measured supply line vltage, in vlts. V 2 is the vltage measured by a vltmeter in series with ne f the leads f the heater being tested, in vlts. R2 is the resistance f the vltmeter measuring V 2' in hms. Figure 51.1 Schematic fr determining insulatin resistance ~ I I I I / CONNECTION MADE TO DEAD METAL PARTS 250 V. D.C. O-JOOV. VOLTMETER POWER SUPPLY TERMINALS S291J O-JOOV. VOLTMETER HAVING R2 INTERNAL RESISTANCE HEATER UNDER TEST

70 60 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, Marking Plate Adhesin Tests 52.1 General T determine if a marking plate secured by cement r adhesive cmplies with 54.37, representative samples are t be subjected t the fllwing tests. In each test, three samples f the marking plates are t be applied t the same test surfaces as emplyed in the intended applicatin. The marking plate is t be applied t the test surface n less than 24 hurs prir t testing The marking plate is cnsidered t cmply with the requirements if immediately fllwing remval frm each test medium and after being expsed t rm temperature fr 24 hurs fllwing remval frm each test medium: a) Each sample demnstrates cmplete adhesin and the edges are nt curled, b) The marking plate resists defacement r remval as demnstrated by scraping acrss the test panel with a flat metal blade 1/16 inch (1.6 mm) thick, held at a right angle t the test panel, and c) The printing is legible and is nt defaced by rubbing with thumb r finger pressure Oven aging Three samples f the marking plates under test are t be placed in an air ven maintained at the temperature indicated belw fr 240 hurs. Maximum nrmal perating temperature f surface f applied label, degrees C (F) Air ven test temperature, degrees C (F) 60 (140) r less 87 (189) 80 (176) r Jess 105 (221) 100 (212) r less 121 (250) 125 (257) r less 150 (302) 150 (302) r less 180 (356) 52.3 Immersin Three samples f the marking plates under test are t be immersed in water at a temperature f 23±2 C (73.4±3.6 F) fr a perid f 48 hurs As-received Three samples f the marking plates under test are t be tested as-received. MANUFACTURING AND PRODUCTION TESTS 53 General 53.1 Each heater shall be subjected t tests which shall include the fllwing The current (r pwer) input t each heater when cnnected t rated vltage shall be n mre than 105 percent f the rated current (r pwer).

71 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL The input may be determined by direct measurement f current (r pwer), r it may be determined indirectly by measurements f resistance and apprpriate cmputatin Each heater shall withstand, withut breakdwn the test ptential specified in 53.5 applied between live parts and dead metal parts The test ptential is t be applied fr 1 minute and is t be 1000 vlts if the heater is rated at 250 vlts r less and is t be 1000 vlts plus twice rated vltage if the heater is rated at mre than 250 vlts; except that the duratin may be reduced t 1 secnd if the value f the test ptential is 120 percent f that specified abve Peridically, tw samples f the heater shall be tested fr cmpliance with 53.2 using instruments which cmply with the fllwing: a) The accuracy is t be 1 percent f full scale value r better. b) The instrument is t have a full-scale deflectin n mre than 3-1/3 times the value t be measured. c) The smallest scale divisin f the instrument is t be in accrdance with Table d) The instrument is t be calibrated at least nce per year by cmparisn with a standard that is traceable t the Natinal Bureau f Standards The manufacturer shall cnduct a prductin-line test n each heater that emplys a tip-ver switch t determine that the switch functins prperly after assembly in the heater. Table 53.1 Instrument scale divisins Ammeters Full scale deflectin, amperes Smallest scale divisin n mre than, amperes Mre than Vltmeters Full scale deflectin, vlts Smallest scale divisin n mre than, vlts Mre than The manufacturer shall keep recrds f his prductin-line tests, available fr review The manufacturer shall test each heater prvided with a pwer-supply crd incrprating a grunding cnductr t ensure that electrical cntinuity exists between an expsed dead metal part f the heater and the grunding blade f the attachment-plug cap, as required by 26.3.

72 62 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, Fr the test mentined in 53.9, the manufacturer is t emply an indicating device (an hmmeter, a lw-vltage battery-and-buzzer cmbinatin, r the like). MARKING AND INSTRUCTIONS 54 Marking 54.1 A heater r electrical accessry shall be rated in amperes, vlt-amperes, r watts (see 54.5) and als in vlts; and if intended fr use n alternating current nly r direct current nly shall be marked t s indicate. The rating shall include the number f phases if the heater is designed fr use n a plyphase circuit, and shall include the frequency (that is, hertz, Hz, cycles per secnd, cps, cycles/secnds, cis), if necessary because f mtrs, relay cils, r ther cntrl devices. The vltage rating shall be any apprpriate single vltage r vltage range such as: , , , , , 550, 575, and Heaters having surfaces which are exempted frm the temperature limits f D.5 f Table 33.1 by the exceptin in nte g shall be marked where readily visible after installatin: "Nt Fr Residential Use," r equivalent If, because f unbalanced lads, the rated current at ne r mre terminals r leads differs frm that at the remaining terminals r leads, the marking shall include the rated current fr each terminal r lead, prperly identified The marked rating fr each terminal r lead, as specified in 54.3 may be mitted prviding: a) The current in any unbalanced leg shall nt exceed the rated current by mre than 5 percent, and b) The size f the pwer-supply cnductrs will be adequate fr the maximum unbalanced lad in accrdance with A fixed r statinary heater that includes a mtr lad f mre than 1/8 hrsepwer (93 W) utput shall have a dual rating as described belw, with each segment f the rating identified. One segment f the rating shall be that f the mtr lad in amperes. The ther segment shall be the rating f the ttal lad ther than the mtr lad (heater lad, lighting lad, r the like), and it may be in amperes r in watts r kilwatts The nameplate marking f a permanently cnnected heater that includes a mtr rated mre than 1/8 hrsepwer (93 W) shall include the minimum circuit ampacity and the maximum current rating f the circuit prtective device If a heater includes an attachment-plug receptacle that is nt intended as a discnnecting means fr any part f the heater r necessary accessry and that may, therefre, serve as a general-use utlet, the added lad that the receptacle may impse n the heater and its supply cnnectins (nt less than 660 watts r 6 amperes per pair f slts) shall be taken int cnsideratin in determining the electrical rating f the heater The requirement in 54.7 des nt apply t an attachment-plug receptacle fr general use as cvered in 21.1.

73 APRIL 11,1994 ELECTRIC BASEBOARD HEATING EaUIPMENT - UL A heater r accessry shall be permanently marked, in such lcatin that the marking will be visible (after installatin in the case f a permanently cnnected heater r accessry ther than a kit which is t be munted n r in the heater itself), with the name r trademark f the manufacturer r private labeler, the catalg number r the equivalent, and the electrical ratings (in accrdance with 54.1 and 54.5) f each circuit t which a supply cnnectin is made The marking shall include the date f manufacture, which may be abbreviated r in an established r therwise acceptable cde that will enable the heater r accessry t be identified as being manufactured within a cnsecutive 3 mnth perid If vercurrent prtective devices are prvided as a separate assembly (see 19.2), the heater shall be marked t indicate that it is t be used nly with this separate assembly The electrical rating shall be cmpletely indicated in the marking, and reference t a wiring diagram fr ne r mre items f the rating is nt acceptable in lieu f including the rating in the marking except as indicated in Fr a heater requiring multiple supply surces, the ratings f the individual circuits f the heater may be shwn n a wiring diagram permanently attached t the heater, and need nt be indicated n the nameplate, which need shw nly the ttal rating Equipment requiring multiple supply surces shall indicate the number f supply surces. If mre than ne discnnect switch may be required t discnnect all pwer, ther than NEC Class 2, within a cntrl assembly r cmpartment, the assembly r cmpartment shall be marked as fllws, r with an equivalent wrding: "CAUTION - HAZARD OF ELECTRIC SHOCK - MORE THAN ONE DISCONNECT SWITCH MAY BE REQUIRED TO DE-ENERGIZE THE EQUIPMENT FOR SERVICING." The marking shall be in letters nt less than 1/8 inch (3.2 mm) in height and shall be f a permanent type lcated n the utside f the cntrl assembly r cmpartment, such as n the cver, r n a statinary (fixed, nnremvable) part inside the cntrl assembly r cmpartment. The warning marking placed inside the cver r n the cnnectin diagram attached t the inside f a cver is nt acceptable Equipment intended t be used nly n a 15 r 20 ampere branch circuit, as indicated in 9.2.5, shall be marked "Use nly n _. ampere branch circuit." See als 19.7 and A transfer switch accessry shall be marked t indicate the maximum current rating f the branch circuit t which it is t be cnnected If a manufacturer prduces r assembles equipment at mre than ne factry, each finished heater and accessry shall have a distinctive marking, which may be in cde, t identify it as the prduct f a particular factry Each heater shall be permanently marked n a surface where it will be readily visible frm the exterir f the heater after the heater is installed r psitined as intended with the fllwing wrding r the equivalent, "CAUTION - High Temperature, Keep Electrical Crds, Drapes, And Other Furnishings Away Frm Heater." The marking shall be in letters nt less than 1/8 inch (3.2 mm) in height and shall be f a permanent type.

74 64 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, Readily visible means visible frm a pint 5 feet (1.52 m) abve the flr and between 1 and 4 feet (0.30 and 1.22 m) away frm the wall with the heater psitined as in the Cntinuus-Operatin Test Each individual heating element r.unit that is a part f a heater and is replaceable in the field shall be marked with its electrical ratings in amperes r watts, and als in vlts A heater r accessry whse acceptable perfrmance depends upn its prper lcatin r psitin shall be marked (such as ''TOp r "BOnOM") t indicate the way in which it is t be installed r used, unless such psitin is bvius frm the external appearance f the heater If the design f equipment cntemplates disassembly by means f a tl fr the purpse f cleaning r similar servicing by the user (including replacement f a thermal cutff) and, if such disassembly invlves the expsure f persns t accidental cntact with any enclsed r prtected live part, the heater shall be marked with a warning that such servicing shuld be dne nly while the equipment is discnnected frm the supply circuit. See als If the servicing r replacement f a cmpnent f a heater r accessry in the field requires the remval r discnnectin f any safety device, a cautin marking shall appear n r adjacent t that device, calling attentin t the fact that it shuld be repsitined in the prper lcatin. The manufacturer's instructins prvided with the equipment shall call specific attentin t this feature If a prtable heater, which is intended t be shipped with the legs detached r in ther than the intended perating psitin, is nt tested with the legs detached r in the shipping psitin, see exceptin t 29.1, it shall be marked in a lcatin where visible with the heater in its intended perating psitin with the fllwing statement r equivalent: "CAUTION - Fire Hazard - D Nt Operate Withut Legs Attached" (r "... Withut Legs In Intended Operatin Psitin"). The marking shall be in letters nt less than 1/8 inch (3.2 mm) in height If any pint within a terminal bx r wiring cmpartment f a permanently cnnected heater in which field-installed cnductrs are intended t be cnnected (including such cnductrs themselves) attains a temperature mre than 60 C (140 F) during the Cntinuus-Operatin Test, the heater shall be marked in accrdance with The statement shall be legible and s lcated that it will be visible during installatin and examinatin f the supply-wiring cnnectins The marking mentined in depends n the size f the supply cnductrs required and n the temperature measured in the Cntinuus Operatin Test. See Table a) If the equipment is t be cnnected nly t a single size branch circuit, the marking is t be "FOR SUPPLY CONNECTIONS USE NO. AWG OR LARGER WIRES SUITABLE FOR AT LEAST _C." r an equivalent statement. b) If the branch circuit size is 15 amperes, the wire size marking may be mitted. c) If the equipment may be cnnected as intended t branch circuits f varius ratings, (because f system installatins, multiple pwer supplies, r ther reasn) the marking is t be "FOR SUPPLY CONNECTIONS, USE WIRES SUITABLE FOR AT LEAST C. SEE TABULATION BELOW FOR WIRE SIZE." r an equivalent statement. d) Unless the equipment is marked in accrdance with t indicate that nly cpper cnductrs are t be used, the markings in (a) and (c), abve, are t indicate the crrect wire sizes fr bth cpper and aluminum (r cpper-clad aluminum) cnductrs.

75 APRIL 11, 1994 ELECTRIC BASEBOARD HEATING EaUIPMENT - UL Table 54.1 Temperature fr marking :) Temperature attained In terminal bx r cmpartment during test Temperature marking C ( F) 75 C (167 F) O.0 C ( F) 90 C (194 F) If the field wiring cnnectin area is s lcated that it is bvius that the field wiring can be lcated and maintained away frm parts' f the heater perating at a temperature rise f mre than 35 0 C (63 0 F), a marking visible during and after installatin f the field wiring cnnectins may be used t indicate the area in which the field wiring and splices are t be lcated after the splice is accmplished A thermally prtected mtr prvided n a heater shall be marked 'IHERMALL Y PROTECTED," and an impedance-prtected mtr prvided n a heater shall be marked "IMPEDANCE PROTECTED." Equipment prvided with pwer supply field wiring terminals shall be marked: a) "USE COPPER CONDUCTORS ONLY" if the equipment is nt intended fr field cnnectin with aluminum wire. b) "USE COPPER OR ALUMINUM CONDUCTORS," "USE COPPER OR COPPER CLAD ALUMINUM CONDUCTORS," r "USE COPPER, COPPER-CLAD ALUMINUM OR ALUMINUM CONDUCTORS" if the equipment is intended fr field cnnectin with cpper r aluminum wire. In either case, an equivalent apprpriate statement may be used in the marking. The marking required shall be independent f a marking n terminal cnnectrs and shall be in a lcatin which is visible during and after cnnectin f the field wiring If a heater cmplies with the requirement in nly when tested in accrdance with (c) (neither A nr B), the heater shall be marked "DO NOT INSTALL LESS THAN INCH ABOVE THE FLOOR" r with an equivalent statement. The dimensin specified in the marking shall be at least 3/4 inch (19 mm) If the enclsure (bx) and the heater unit f the heater are nt shipped fully assembled, r if it is necessary t remve the heater unit (including assciated wiring) frm a recessed type enclsure fr installatin, the enclsure shall be marked with: a) The name r identifying symbl f the manufacturer r private labeler, b) The catalg number r the equivalent f the enclsure (bx), and c) If the field wiring system is t be cnnected t the enclsure, any required infrmatin regarding the wiring necessary fr intended installatin. See In the case f an enclsure (bx) which is intended t be installed prir t installatin f the heater unit, the marking shall be visible after the enclsure is installed. The heater unit shall be marked, where the marking will be visible when the pwer-supply cnnectins are being examined, t specify the enclsure (bx) in which it is intended fr installatin.

76 66 ELECTRIC BASEBOARD HEATING EQUIPMENT - UL 1042 APRIL 11, If the guard f a heater is remvable (that is, if it is intended t be remved fr shipping r strage) the heater shall be legibly marked, in a lcatin where the marking will be visible after the heater has been installed as intended, with a warning that it shuld nt be perated unless the guard is in place If an accessry is a kit intended t be munted n r in a heater, the heater shall be apprpriately identified n the accessry marking. If an accessry is intended t accmmdate cmpnents which are nt a part f the accessry, the accessry shall be marked t indicate the type f cmpnents t be prvided. See als If the attachment plug receptacle f a receptacle accessry is nt prvided with the accessry as indicated by 21.5 and 21.6, the accessry shall be permanently marked t indicate that the receptacle prvided is t be f the grunding type If parts f basebard heaters nt expsed t cntact during intended peratin are expsed during cleaning r similar servicing in accrdance with the manufacturer's instructins, and have sharp crners, edges, r prjectins, the heater shall be marked "CAUTION," and with the fllwing r equivalent wrding: "Fins May Cause Cuts - D Nt Tuch. The marking shall be in letters nt less than 1/8 inch (3.2 mm) in height, shall be f a permanent type, shall be visible when the cver is remved, and shall be n a fixed (nnremvable) part f the enclsure Unless therwise specified, all required markings shall be permanent and shall be lcated n a part that cannt be remved withut the use f tls, but shall nt be lcated n a part which may be discarded and replaced by an accessry kit unless the required markings appear als n the replacement part r at anther lcatin n the heater Ordinary usage, handling, strage, and the like, f the heater r accessry shall be cnsidered in the determinatin f permanence f marking. Etched, mlded, r die-stamped markings are generally cnsidered t be permanent. Paint stenciled r ink-stamped types f markings are cnsidered t be permanent if they resist defacement as demnstrated by scraping with a 1/16 inch (1.6 mm) thick flat metal blade held at a right angle t the surface and the printing is legible and nt defaced by rubbing with thumb r finger pressure. In additin, paint stenciled r ink-stamped markings n exterir enclsure surfaces are t be rubbed several times with a damp clth t ensure that the ink r paint is nt water sluble. Marking plates secured by adhesive shall be investigated and shall be adequate fr the particular applicatin (see 52.1). 55 Instructins 55.1 A cpy f the installatin and perating instructins intended t accmpany each heater r cmpnent, r equivalent infrmatin, is t be used as a guide in the examinatin and test f the heater r cmpnent. Fr this purpse, a printed editin is nt required The instructins shall include such directins and infrmatin as deemed by the manufacturer t be necessary fr the installatin, maintenance, and use f the heater r cmpnent Clear and cmplete instructins fr the installatin and peratin f a basebard-type heater system shall be prvided. The instructins shall include the fllwing items: a} A cmplete electrical diagram f the heater system, shwing the cnnectins f the pwer supply and the intercnnectin f individual cmpnents. b} Illustratins f essential features, shwing the relatin f cmpnents.