Sentron SMP Switchboards

Transcription

1 8 SWTBOARDS Sentron SMP Switchboards onstruction Details Simplified system design. A typical SMP switchboard consist of a floor mounted, wall supported service section, and a distribution section. The wireway can also be added where required by the local utility or if additional cable termination space is required. Wireways are modular to allow flexibility The wireway is available in 2 depths to suit customer needs. Wireway has split front doors as standard with optional hinged doors. The lug pads are standard NMA hole pattern and accept up to 5 mechanical lugs or 6 compression lugs. Service ntrance Sections house a variety of equipment. b Service ntrance Sections. Service sections can be fed directly from overhead by cable. Service entrance sections equipped for bottom feed will accept cable from underground directly into the service section. b Utility Metering n addition to the main device, the service section contains utility metering provisions. old metering provisions (T s on the load side of the main device) are furnished. The T s are provided by the utility company. The compartment will be built to utility company standards, with hinged doors and provisions for utility metering equipment. b User Metering The service section provides space for the Siemens Digital Meter with remote display, and it s associated components. b Main protective device The MB is mounted individually so that it can be located quickly in an emergency. SMP switchboards will accommodate different types of main circuit breakers. Selection depends on the characteristics of your individual electrical system. Distribution Sections have ample wiring room and front accessibility. Generous top or bottom gutters have been created by locating the bus-link in the top or bottom of the distribution section, so there s ample room to run cables into the distribution section and make connections. Standard bolted covers allow complete access to load conductors. Future flexibility comes standard in the Siemens SMP switchboard. The distribution section can accommodate any combination of panel mounted devices, including MBs and fusible disconnect switches. Operating temperatures are in accordance with SA Standards Bus bars are available in standard tin-finished aluminum or optional silver-finished copper. Standard bus is sized on the basis of heat rise criteria, in accordance with SA 22.2 #31. All bus bars are sized to limit heat rise to above an ambient temperature of 40. onstruction Bus-Link onnections are accessible from the front. The Bus-Link can be bolted from the front of the switchboard. ach bus-link is attached by grade five bolts to assure solid joints between sections, and to maintain full bus ampacity through the joint. To make installation and servicing of the bus-link easier, all phase and neutral busses are stacked one above the other. able Terminals Screw mechanical connectors (lugs) are provided as standard equipment. 8-2 Siemens anada Limited Power Product atalogue 2014

2 SMP Switchboard ntroduction Whether the design is for a 240V A, 400 ampere system; a 600V A, 1 A ampere system; or something in between, Siemens Sentron Switchboards should be considered. very aspect of design has been aimed at improving layout convenience, reducing installation costs, and minimizing the impact and cost of system changes. These switchboards provide the space saving construction and service flexibility necessary in systems for light industrial plants, retail strip malls, and commercial buildings. Service entrance sections of the SMP accepts a wide range of Sentron Molded ase ircuit Breakers as main disconnect devices. The SMP switchboard is designed for special configurations. t can be equipped with incoming and outgoing cable/conduit connections, supplied with metering and other special features. The distribution sections of all Sentron Switchboards are designed with improved wiring space and greater accessibility. They re also designed for easier installation and maintenance. onveniently located bus-link without compromising useful wiring gutter space, and standard bolted gutter covers offer complete access to load conductors. Front accessibility to bus and protective devices makes adding or replacing circuit breakers or switches quick and easy. SMP Switchboard Features and Ratings b Main bus rated up to 1 ampere. b Rear of all sections aligned so that switchboard can be floor mounted and secured against the wall. b Front connected and front accessible. b Main devices individually mounted. Molded ase Breaker: amps. b Branch Devices panel mounted. Molded ase Breaker: 15 1 amps fixed. Quick-Make Quick-Break Fusible Switch: A SMP Specifications (Table 1) nclosure Type Dimensions Main or Distribution Wireway Volts SMP Switchboard MA 1 Dripshield (option) 38 W x 90 x Dp 24 W x 90 x Dp or.5 Dp 600V Max Amperes 400-1A Bus Type Bus Bracing nterrupting apacity ntry Main Device Branch Devices (Unit Space) Metering Devices Other Options Aluminum (tin plated) opper (silver finished) optional 50 KA KA (optional) Main and Distribution Section Dimensions (Table 2) Switchboard Type 50 KA KA (optional) able only (top or bottom) MB 400-1A b 80% Rated b % Rated (option) 52.5 in Main with Distribution Section, or 22.5 in MUD Section, or 60 in Distribution Section General Siemens Digital Meter with Remote Display SADU (option) Feeder Breakers Only SPD Units Sill hannels (1.5 ) Lifting ooks Access Revised 02/19/2015 Dimensions - nches (mm) W D SMP Front 90 (2286) 38 (9) (324) 600 Volts A Maximum 1 Ampere Mains 1 Ampere Maximum Branch SA Short ircuit Rating,000A R Maximum SA ertified To: AN/SA-22.2 No. 31-M89 SA File #LR (49454) 8 SWTBOARDS a Only available as a Wireway. Siemens anada Limited Power Product atalogue

3 8 SWTBOARDS Sentron SMP Switchboards Protective Devices - Molded ase ircuit Breakers Standard Breakers are designed for commercial, industrial, institutional and other heavy duty applications. They are rated up to 600V A and 0V D. Their interrupting ratings are higher than normal duty breakers. igh nterrupting Breakers are designed for heavy duty applications where the interrupting requirements exceed the ratings of heavy duty breakers. They are rated up to 600V A. urrent Limiting Molded case breakers incorporate the exclusive -T- blow-apart interruption principle. They meet the SA requirements for current-limiting breakers. urrent-limiting circuit breakers can limit the let-through 2 t to a value less than the 2 t of one-half cycle wave of the symmetrical prospective current without any fusible elements when operating within their current-limiting range. Main Breaker Selection (Table 3) (KA) Max Ampere Breaker atalogue Rating Type Number 240V 480V 600V Available Trip Values XD6 X, 2, 0, 300, 0, 400 D6 6, 2, 0, 300, 0, 400 D6, 2, 0, 300, 0, 400 D6, 2, 0, 300, 0, 400 SD6 S, 300, 400 SD6 S, 300, 400 SD6 S, 300, 400 LXD6 LX 450, 500, 600 LD6 L6 0, 300, 0, 400, 450, 500, 600 LD6 L 0, 300, 0, 400, 450, 500, 600 LD6 L 450, 500, 600 SLD6 SL 300, 400, 500, 600 SLD6 S6 300, 400, 500, 600 SLD , 400, 500, 600 MD6 M6 50 MD6 M 50 MD6 M SMD6 SM , 700, 800 SMD6 S , 700, 800 SMD , 600, 800 ND6 N , 900, 0, 1 1 ND6 N , 900, 0, 1 ND6 N 900, 0, 1 SND6 SN , 0, 1 SND6 S , 900, 0, 1 SND6 800, 900, 0, (6) 10.0 (4) 8. (210) 7.9 (201) (193) (299) 13.4 (341) (227) 13.0 (330) 12.0 (305) 13.0 (330) Selection Branch Breaker Gutter Dimensions For 38 W Distribution Section (Table 5) A B D F G K M A B D F 3.75 (95) 3.75 (95) 5.00 (127) 5.00 (127) 5.00 (127) 3.75 (95) (4) (4) 8-4 Siemens anada Limited Power Product atalogue 2014

4 Branch ircuit Breaker Selection a (Table 4) Selection Breaker Type Available Trip Value Ampere Ratings Mounting eight - nches (mm) Max Rating (KA) Twin Single Gutter f 240V 480V 600V BL 15, 20, 30, 40, 50, 60, 70, 80, 90, 3.75 (95) A 10 BLF (GF) 15, 20, 30, 40, 50, (95) A 10 BL (GF) 15, 20, (95) A 10 BL 15, 20, 30, 40, 50, 60, 70, 80, 90, 3.75 (95) A 22 BL (GF) 15, 20, 30, 40, 50, (95) A 22 BQD6 e 15, 20, 30, 40, 50, 60, (95) A D2 15, 20, 30, 40, 50, 60, 70, 80, 90, 3.75 (95) 3.75 (95) B D4 15, 20, 30, 40, 50, 60, 70, 80, 90,, 110, (95) 3.75 (95) B D6 15, 20, 30, 40, 50, 60 70, 80, 90,, 110, 1 D6 15, 20, 30, 40, 50, 60, 70, 80, 90, 110, 1 Q2 Q2 Q2- FXD6 FD6 FD6 XD2 XD6, D6 D6 D6 SD6 SD6 SD6 LXD6, LD6 LD6 LD6 SLD6 SLD6 SD6 LMD6 LMD6 MD6 MD6 MD6 SMD6 SMD6 SMD6 ND6 ND6 ND6 SND6 SND6 SND6 Breaker Type 60, 70, 80, 90,, 1,, 175,, 2 60, 70, 80, 90,, 1,, 175,, 2 60, 70, 80, 90,, 1,, 175,, 2 70, 80, 90,, 1,, 175,, 2, 0 70, 80, 90,, 1,, 175,, 2, 0 70, 80, 90,, 1,, 175,, 2, 0, 2, 0, 300, 0, 400, 2, 0, 300, 0, 400, 2, 0, 300, 0, 400, 300, 400, 300, 400, 300, 400, 300, , 500, 600 0, 300, 0, 400, 450, 500, , 500, , 400, 500, , 400, 500, , 400, 500, , 700, , 700, , 600, , 900, 0, 1 800, 900, 0, 1 800, 900, 0, 1 800, 0, 1 800, 900, 0, 1 800, 900, 0, 1 Available Trip Value Ampere Ratings 3.75 (95) 3.75 (95) B 3.75 (95) 3.75 (95) B 3.75 (95) 3.75 (95) F 3.75 (95) F 10 (4) 10 (4) 10 (4) 10 (4) 10 (4) 10 (4) 10 (4) 10 (4) D D G M M K K Max Rating (KA) Mounting eight - nches (mm) Twin Single Gutter (mm) 240V 480/277V 480V 600/347V 600V NGB 15, 20,, 30,, 40, 50, 60, 70, 80, 90,, 110, (95) 13.98" (5) 14 NB B NDG LDG NFG LFG 15, 20,, 30,, 40, 50, 60, 70, 80, 90,, 110, 1 15, 20,, 30,, 40, 50, 60, 70, 80, 90,, 110, 1 50, 60, 70, 80, 90,, 110, 1, 50, 60, 70, 80, 90,, 110, 1,, 110, 1,, 175,, 2, 0, 110, 1,, 175,, 2, (95) (295) 5.00 (127) (276) 5.00 (127) (276) NG 0, 300, 0, (158.75) 6. (158.75) 13.42" (341) SWTBOARDS Space includes housing frame plate with blank cover plate. Provision includes all necessary mounting hardware, less circuit breaker, and includes housing frame cover plate with breaker handle opening. 1 to 6 poles may be mounted in 3.75 (95) of unit space Accessories such as shunt trips on three pole breakers require 6. (159) of unit space. Ground fault is not available on branch Sensitrip breakers. e Also 10KA at 600Y/347 Volts. f Refer to Table 5 for layout dimensions. Siemens anada Limited Power Product atalogue

5 Protective Devices - Fusible Disconnects Selection Fuse Selection The Proper Fuse Type for the Application is Selected Using the Following Parameters: b Voltage Requirements b onductor Ampacity b orsepower Requirements b Maximum Available RMS Fault urrent b SA Fuse lass Maximum VB P Ratings (Table 6) Volts Amp 3 Phase Single Phase Rating Branch Switch onnectors (Table 10) d Switch Ampere Rating Wire and able Range 30 (1)#14 #4 AWG (u or Al) 60 (1)#14 #4 AWG (u or Al) (1)#10 #1/0 AWG (u or Al) (1)#6 AWG-0kcmil (u or Al) 400 (1)#1/0 AWG-750 MM OR (2)#1/0 AWG-0 MM (u or Al) 600 (1)#1/0 AWG-750 MM OR (2)#1/0 AWG-0 MM (u or Al) Branch Switch Gutter Dimensions Maximum VK P Ratings (Table 9) For 38W Distribution Section (Table 8) Volts Amp 3 Phase Single Phase 7.5" (191) 6." (159) Rating /30A VK Switch " (191) 6." (159) /60A VK Switch 7.5" (191) /A VK Switch 7.5" (191) Gutters (Table 12) nd Gutters Side Gutters Ampere Minimum - Minimum - Rating nches (mm) nches (mm) (305) 7.9 (201) (305) 7.9 (201) 5.0" (127) /A VK Switch 10.0" (4) 10.0" (4) 30/30A VB Switch 7.5" (191) 10.0" (4) 10.0" (4) /A VB Switch 7.5" (191) 8.0" (203) 9." (2) 60/60A VB Switch 7.5" (191) /A VB Switch 10.0" (4) 400A thru 600A VB Switch 15.0" (381) Branch Switches 600V Maximum (Table 11) Rating Max Fusing Mounting eight Ampere Voltage 38 W 30/30A & 60/60A (VK) e 600V lass,, R 6. (159) /A (VK) e 600V lass,, T 7.5 (190) /A (VK) e 600V lass,, T 10.0 (4) 30/30A & 60/60A (VB) 600V lass 7.5 (190) /A (VB) 600V lass 7.5 (190) /A (VB) 600V lass R,, T 10.0 (4) 400A & 600A (VB) 600V lass,r,,t 15.0 (381) Switch Accessories (Table 13) Fuse Pullers (VK) at. No. 30 or 60 Amp FP2 Amp FP3 Amp FP4 8 SWTBOARDS SA Fuse lasses (Table 14) nterrupting lass Amperes Volts (A) Ratings 2 t, p (Let-Thru) ircuits Standard ode 1-600A 0 and 600V 10,000A Less than or less 10,000A available K a Fast Acting 1-600A 0 and 600V 50,000A Feeder circuits (One time) or less Fast Acting 1-600A 600V or less To,000A p and 2t-Low Feeder circuits and Time Delay (motor load small %) Motor circuits RK1 Fast Acting 1/10-600A 600V or less To,000A 2t-Slightly > Feeder circuits and Time Delay 0V or less p-slightly > Motor circuits RK5 Fast Acting 1/10-600A 600V or less To,000A 2t- > RK-1 Feeder circuits and Time Delay 0V or less p- > RK-1 Motor circuits Moderate 2-600A 600V or less To,000A 2t- < RK-5 Motor circuits (FORM ) Delay p- < RK-5 T Fast Acting 1-600A 300 and 600V To,000A 2t-Low Non-motor loads or less p-low L Fast Acting A 600V or less To,000A 2t-Low Feeder circuits and Time Delay p-low motor loads Motor circuits Fuse clips do not prohibit the use of lass type fuse in switch. Refer to Siemens for single phase and D horsepower requirements. Ratings are based on UL test procedure. d onnector range applies to VB Switches only. 5 Not suitable for use in distribution space in main section. 8-6 Siemens anada Limited Power Product atalogue 2014

6 Replacement or Modification omponents for ircuit Breakers or Fusible Switches g onnecting Strap Kits For Use With ircuit Breakers n Distribution Sections dh (Table 15) eight - atalogue Breakers nches (mm) Number BQ, BQ, B BL, BL, BL 3.75 (95) 6BL2 c D2, D4, D6, 3.75 (95) D (95) 662 c D (95) 6L2 Q2, Q2, Q2-6Q2 FXD6, FD6, FD6 6F62 FD6 6LF1 XD2, XD6, D2, D6, D6 662 SD6, SD6 D6, SD6 6L1 LXD6, LD6, LD6, SLD6, SLD6 6LL61 LD6 6LL1 SLD6 6SL61 MD6, MD6, 10 (4) MD6, SMD6 10 (4) 6M61 These are aluminum connectors. f copper is required please add suffix (95) plate accommodates six 1-pole breakers. 10 (4) plate accommodates eighteen 1-pole breakers. onnector kits also accommodate S5, F2, DP Panelboards, FRS, F and F distribution interiors or DP6/SPP6 Series Panels. Special onstruction, Additions and Accessories When required, special constructions or additions to standard Switchboards may be specified for all factoryassembled Switchboards. Listed below are those available for Type SMP Switchboards. 1. nclosure Type 38 nclosure MA Types Type 1 (ndoor or Drip-proof) Type 1A (Front Gasketed) 2. Wireway Options These connectors are available in copper only. f Blank (ircuit Breaker or Switch) over Plates can also be used in F and F distribution interiors or DP6/SPP6 Series Panels. g Please refer to the Siemens Speedfax for detailed circuit breaker or switch information. Selection 10. ircuit Breaker Accessories andle Blocking Device Blocks handle in either the ON or OFF position. Available for: 24 W x 90 x Dp inged Door MD6, MD6, MD6, SMD6, Door overs ND6, ND6, ND6, SND6 MN6BL 24 W x 90 x.5 Dp inged Door Door overs Padlocking Device - Padlocks in OFF 3. Painted Finish position. Available for: Touch-Up Paint (ASA61, Light Grey) Breaker Type at. Number 12 oz. aerosol can, at. # TUP-61 BL, BL, BL, ND6, ND6, ND6 10 (4) QLD3 BQ, BQ, BQ, B6, BQXD SND6, SND6, 10 (4) 6N61 SND6 10 (4) 4. Miscellaneous Accessories One pole, BL, BLF, B, BAF PLD1 onnecting Strap Kits For Use With ircuit Nameplate - laminated and engraved Two-pole, BL, BLF, and B PLD2 Breakers in S5 and SPP6 Series Panels 5. Bus-Link (One Set Per Panel) Q2, Q2, Q2- L9419 eight atalogue Breaker Type Mounting BQD, QD BQDPLD (mm) Number Ampere Unit Space Occupied in MUD - D4, D6, D4, D6 D2PL NGB 3.75 Rating nches (mm) (95) D SNBD j onsult Factory FXD6, FD6, FD6, FD6 FD6PL1 NB, B 3.75 XD6, D6, D6, D6, SD6, D6PL (95) D SBD j 6. Grounding of SMP Switchboard LXD6, LD6, LD6, LD6, SLD6 NDG, DG, LDG 5.00 (127) D SDGD j MD6, MD6, MD6, SMD6, MN6PLD Non-nsulated quipment Ground Bus ND6, ND6, ND6, SND6 NFG, FG, LFG 5.00 ncluding Ground Lug (127) D SFGD j ontinuous Solid opper Ground andle xtensions - For replacement NG, G, LG 6. (158.75) D SG2D j (optional) (one extension shipped with breaker) NG, G, LG 6. (158.75) S SG1D j 7. Main Bus Breaker Type at. Number onnecting Strap Kits For Use With VB, VK or P MD6, MD6, MD6, SMD6, X11 Standard Main bus and Neutral bus are Switches in Distribution Sections dh (Table 16) ND6, ND6, ND6, SND6 tin plated aluminum or silver finished Rating VB Switch VK Switch P Switch copper (option). Amperes at. No. at. No. at. No. Ground Fault Sensing Relay Kit 30/30 N/A VK6-57 N/A 8. Lugs quipment Protection (30 ma) 60/60 VB6-71 VK6-57 N/A For Main Device and Neutral For Use with Number atalogue Number / N/A VK6-58 N/A For Main Breakers please see SpeedFax Breaker Types of Poles Description VB6-71 N/A N/A section #6 D4, D6, See breaker section Neutral - please consult factory D4 1, 2, 3 of this catalogue. / N/A VK6-72 N/A VB6-71 VK6-71 i N/A VB6- N/A N/A 800 N/A N/A F6162DAN Blank over Plates For Distribution Switch or ircuit Breaker f (Table 17) For use with SMP Switchboards. eight - atalogue nches (mm) Number 1. (32) 6FPB (64) 6FPB (95) 6FPB (127) 6FPB (4) 6FPB (381) 6FPB15 9.SPD Modules Sentron TPS3 05 KA KA KA 0KA 300KA Options: Surge ounter Remote Monitor Breaker Type at. Number BL, BL, BL, QL1 Q2, Q2, Q2- QS1 BQD, QD, NGG BQDBD D4, D6, D4, D6 2BL FXD6, FD6, FD6, FD6 FD6B1 XD6, D6, D6, D6, SD6, D6BL LXD6, LD6, LD6, LD6, SLD6 Shunt Trip on Main and Branches at. Description Number BL, BQD6 (branch only) See breaker section Q2, Q2, Q2, D2, D4, D4 (branch only) of this All others through 1A catalogue. h Mounting kits include connector straps and covers (breakers or switches are not included). i Refer to Siemens for units equipped with auxiliary switches. j onsult Sales for mounting in F/F Switchboards. Siemens anada Limited Power Product atalogue SWTBOARDS

7 8 SWTBOARDS Sentron SMP Switchboards A. Scope Furnish and install, as shown on the plans, a secondary distribution switchboard, as specified herein, for the system indicated below: 120/208V 3-phase 3-wire 347/600V 4-wire 600V B. onfiguration The switchboard enclosure shall be of bolted construction: MA 1 indoor. MA 1 with dripshield (optional). MA 1 with Front Gasketed (optional). Switchboard shall be bolted together to form one metal enclosed rigid switchboard. Switchboard shall include all protective devices and equipment as listed on drawings with necessary interconnections, instrumentation and control wiring. All groups of control wires leaving the switchboard shall be provided with terminal blocks with suitable numbering strips. The switchboard shall have space or provisions for future expansion as noted on the plans. Switchboard shall be constructed and certified in accordance with SA standards and shall be Siemens type (SMP) or approved equal. ndividual sections shall be front accessible, not less than (324) deep, and the rear of all sections shall align. Distribution sections shall be designed to accommodate the intermixing of Molded ase Breakers and Fusible Disconnects in the same distribution interior.. Bus Requirements The bus shall be tin-finished aluminum silver-finished copper (option) of sufficient size to limit the temperature rise to. The bus shall be braced for 50,000 or,000 (option) amperes symmetrical and supported to withstand mechanical forces exerted during short circuit conditions when directly connected to a power source having the indicated available short circuit current. D. ncoming Service Overhead or Underground Service: able ntry This section shall be bussed and sealable per local utility requirements. Screw-type mechanical lugs, compression lugs to terminate, aluminum, copper cable, shall be kcmil, and cables per phase. Main breaker standard aluminum mechanical lugs suitable for aluminum or copper. (No wireway). Metering Service Section The service section shall be designed for the system parameters indicated in section A above. The metering service section shall have a Utility Metering compartment per utility requirements. User metering as indicated below and as shown on plans. Main (service) section: Siemens Digital metering with remote display current transformer(s) /5 or suitable rating Branch circuits (Sensitrip only): SADU Meter Display (option) Ground fault Protection (3-Phase, 4-Wire): Furnish and install on the service equipment and/or switchboard a Ground Fault protection system and indication equipment as specified herein and as shown on drawings in accordance with Section All new Ground Fault Protection and ndication equipment shall be factory installed, wired and tested by the switchboard manufacturer. F. Switchboard SMP Guide Specification The complete switchboard shall be finished with light grey, ASA-61 paint. ach switchboard main section shall have a metal nameplate permanently affixed to it, listing the following information: b Name of manufacturer b System voltage b Ampacity b Type b Manufacturer s shop order number and date b ach section of switchboard shall bear a SA certification mark and a short circuit rating label. The switchboard shall be per the arrangement below. F1. Switchboard Type Panel-Mounted, Front Accessible. Switchboard shall be of Siemens SMP type, or approved equal. ndividual sections shall be front accessible, floor mounted rear supported, not less than (324) deep, and rear, of all sections shall align. ncoming line termination, main device connection and all bolts used to join current-carrying parts shall be installed so as to permit servicing from the front only so that no rear access is required. The branch devices shall be front removable and panel mounted with line and load side connections front accessible. G. Main Protective Devices The main protective device, to be installed in the main device section, shall be as indicated below: G1. Molded ase ircuit Breaker Molded case circuit breaker shall be of the quick-make, quick-break, trip-free, (standard) (igh nterrupting) (urrent Limiting) (solid state Sensitrip ) type. t shall be frame (3-pole) (240V) (600V) breaker with a trip current rating of: 400A, 600A, 800A, 0A a, Ground fault protection required, per section when the current is O 0A at 600 volts. Specification 1 A a of an interrupting capacity of not less than amperes RMS symmetrical at the system voltage. The following accessory options are to be included: Shunt trip Ground fault relay Long time (Sensitrip only) Long time delay (Sensitrip only) Short time (Sensitrip only) Short time delay (Sensitrip only) ntegral ground fault (Sensitrip only) Other (list). Branch Protective Devices (Select as necessary) All molded case circuit breakers, and fusible disconnect units used as a protective device in a branch circuit will meet the requirements of the appropriate paragraph below 1. Molded ase ircuit Breaker Molded case circuit breakers shall be of quick-make, quick-break, trip-free (thermal magnetic type) (current limiting) (solid state) with frame, trip and voltage rating, either 2-pole or 3-pole, as indicated on the plans. All breakers shall have an interrupting capacity of not less than amperes RMS symmetrical at the system voltage. All breakers shall be removable from the front of the switchboard without distributing adjacent units. The switchboard shall have space or provisions for future units shown on the plans. 2. urrent Limiting ircuit Breaker urrent limiting circuit breakers shall provide inverse time delay, instantaneous circuit protection, and also limit the letthrough 2 t to a value less than 2 t of one-half cycle wave of the symmetrical prospective current without any fusible elements. Breakers shall have an interrupting capacity of not less than ampere RMS symmetrical at the system voltage. 3. Fusible Disconnect Fusible disconnects shall be quick-make, quick-break units utilizing the double-break principle of circuit rupturing to minimize arcing and pitting and shall conform to the ratings shown on the plans. ach disconnect shall have an individual door over the front, equipped with a voidable interlock that prevents the door from being opened when the switch is in the ON position unless the interlock is purposely defeated by activation of the voiding mechanism. All disconnects shall have externally operated handles. Disconnects shall be equipped with lass (standard), lass R rejection type, lass L (standard), lass T fuse holders as indicated on the plans suitable for application on system with amperes symmetrical available fault current. 8-8 Siemens anada Limited Power Product atalogue 2014

8 Fault-urrent alculation on Low- Voltage A Systems n order to determine the maximum interrupting rate of the circuit breakers in a distribution system it is necessary to calculate the current which could flow under a three-phase bolted short circuit condition. For a three-phase system the maximum available fault current at the secondary side of the transformer can be obtained by use of the formula: l sc = kva x KV x 3 x % Z l sc = Symmetrical RMS amperes of fault current. kva = Kilovolt-ampere rating of transformers. KV = Secondary voltage in kilovolts. %Z = Percent impedance of primary line and transformer. Application ntegrated quipment Short ircuit Ratings The term ntegrated quipment Short ircuit Rating refers to the application of series connected circuit breakers in a combination that allows some breakers to have lower individual interrupting ratings than the available fault current. This is permitted as long as the series combination has been tested and certified by UL & SA. Series ratings must be specified on order at time of entry. For more information on series ratings please consult your local Siemens sales representative. Normal load and Fault urrents of Three Phase Transformers (Table ) Trans- Maximum 208 Volts, 3 Phase 240 Volts, 3 Phase 480 Volts, 3 phase 600 Volts, 3 Phase former Short-ircuit Rated Short-ircuit urrent Rated Short-ircuit urrent Rated Short-ircuit urrent Rated Short-ircuit urrent Rating Kva Load RMS Symmetrical Amps. Load RMS Symmetrical Amps. Load RMS Symmetrical Amps. Load RMS Symmetrical Amps. 3 Phase Available ontin- Trans- 50% om- ontin- Trans- % om- ontin- Trans- % om- ontin- Trans- % om- Kva and from uous former Motor bined uous former Motor bined uous former Motor bined uous former Motor bined imped- Primary urrent, Alone Load urrent, Alone Load urrent, Alone Load urrent, Alone Load ence % a System Amps Amps Amps Amps % Unlimited % Unlimited % Unlimited % Unlimited SWTBOARDS Short circuit currents are calculated with impedences and kva shown in this table. Short circuit current contributions are calculated on the basis of motor characteristics that will produce four times normal current. 50% motor load contribution is assumed for 208V and % motor load contribution is assumed for 240V, 480V and 600V. This Table has been prepared to list the symmetrical RMS fault current which is available at the secondary terminals of the transformer. Siemens anada Limited Power Product atalogue