Approved Contractor Construction e-guide Residential Commercial Clark Public Utilities PO Box 8900 Vancouver, WA 98668
(PAGE 2) TABLE OF CONTENTS PAGE Trenching 3 Wire 8 Single-Phase Transformer Set 13 Secondary Pedestal 36 Lighting 42 Metering 45 Three-Phase Transformer Set 55 Padmount Transformers 60 Single-Phase J-Box 62 Three-Phase J-Box 64
(PAGE 3)
(PAGE 4)
(PAGE 5)
(PAGE 6)
(PAGE 7)
(PAGE 8)
(PAGE 9)
(PAGE 10)
(PAGE 11)
(PAGE 12)
(PAGE 13)
(PAGE 14)
(PAGE 15)
(PAGE 16)
(PAGE 17)
(PAGE 18)
(PAGE 19)
(PAGE 20)
(PAGE 21)
(PAGE 22)
(PAGE 23)
(PAGE 24)
(PAGE 25)
(PAGE 26)
(PAGE 27)
(PAGE 28)
(PAGE 29)
(PAGE 30) Clark Public Utilities Commercial Electric Service Handbook Transformer location and access Underground electrical facilities must be readily accessible by the utility during construction and for future operation and maintenance. The area around padmounted electrical equipment must provide a clear and level working space and remain free from obstructions such as landscaping, poles, retaining walls, structures, fences, etc. All transformers and padmounted equipment are to be located: Within 10 feet of a drivable surface but not closer than 5 feet (Figure 3). With the front of the equipment (door and lock side) facing toward the drivable surface. With the transformer pad parallel to the edge of the drivable surface. Allowing 10 feet of clearance in front and 3 feet from the back and sides of the equipment (Figure 3). At least 2 feet from a sidewalk for pedestrian safety. Figure 3 Commercial padmounted transformer location and access VIEW FROM ABOVE 3 ft. minimum of clear working space from back and sides 2 ft. minimum of clear working space from a sidewalk to front of transformer pad sidewalk transformer door and lock edge of transformer pad 5 ft. minimum to 10 ft. maximum of clear working space from drivable surface to front of transformer pad curb position transformer with door and lock facing the drivable surface drivable surface Chapter 3: Commercial Underground Services / January 2011 17
(PAGE 31) Clark Public Utilities Commercial Electric Service Handbook Transformer safety clearances Clearances from padmounted transformers to structures are measured from the nearest metal portion of the transformer to the structure or any overhang. The clearance from a building is 10 feet if the building has combustible walls, and 3 feet if the building has non-combustible walls as shown in Figure 4. Table 4 provides additional safety clearances that apply to any oil-filled electrical equipment. Figure 4 Commercial padmounted transformer minimum safety clearances non-combustible structure and roof combustible structure and roof 3 ft. min. transformer 10 ft. minimum 3 ft. 10 ft. transformer operable window or other opening 10 ft. door or other opening 10 ft. 10 ft. fire escape fuel dispensing facilities 20 ft. 15 ft. gas meter 6 ft. hydrant transformer 10 ft. fuel storage 18 Chapter 3: Commercial Underground Services / January 2011
(PAGE 32) Clark Public Utilities Commercial Electric Service Handbook If the distance between the corner posts exceeds 5 feet, a removable center post is required (Figure 5). If a removable center post is installed, the threaded joint requires treatment with an anti-seizing agent. Paint exposed section of post traffic yellow. Figure 5 Guard post (bollard) installation for commercial transformers FRONT VIEW do not fill center post with concrete domed concrete 3 ft. minimum coupling FINAL GRADE 2 ft. concrete fill 4 in. galvanized/steel pipe, concrete filled removable center post, as required 4 in. galvanized/steel pipe, concrete filled VIEW FROM ABOVE edge of transformer pad edge of transformer commercial transformer 18 in. minimum on 45 door and lock removable center post, as required NOTE: Additional guard posts may be required at back and sides of transformer. 20 Chapter 3: Commercial Underground Services / January 2011
(PAGE 33)
(PAGE 34)
(PAGE 35)
(PAGE 36)
(PAGE 37)
(PAGE 38)
(PAGE 39)
(PAGE 40) Clark Public Utilities Residential Electric Service Handbook Figure 7 Typical secondary trenches to underground utility sources secondary trench to padmount transformer #### FRONT OF TRANSFORMER transformer number transformer lock NOTE: Clark Public Utilities personnel will route wire into energized facilities. leave 8 ft. tail of triplex wire at transformer use the utility provided white paint mark to position trench (or use transformer lock if mark is not shown) 2 ft. secondary trench to secondary pedestal view from side 2 ft. to 2-1/2 ft. open NOTE: Clark Public Utilities personnel will route wire into energized facilities. 8 ft. of makeup wire 18 in. minimum cover to top of conduit view from back 24 in. trench depth 2 ft. bushing required, do not permanently attach to conduit 6 in. conduit aimed at center of pedestal (leave 2 feet between end of conduit and pedestal) Chapter 3: Underground Secondary Services / February 2010 17
CHAPTER3 Clark Public Utilities Residential Electric Service Handbook (PAGE 41) Underground Secondary Services Preparing for the installation Typically, an extension of secondary 120/240 volt electrical service is all that is required if less than 200 feet of secondary voltage wire is needed to connect the meter socket to a transformer. For homes with large motor loads such as multiple heat pumps or dryers, air conditioning units, etc., this distance may be less. All single-family residences not located within 200 feet of existing primary require an underground primary line extension to place a transformer closer to the structure. See Chapter 4, Primary Line Extensions, for more information on this type of installation. The following checklist will assist in preparing a project for the installation of secondary underground electric service. After these items have been completed, Clark Public Utilities will connect the service and set the meter (Figure 4). Figure 4 Typical underground secondary service meter base (ground per NEC) secondary pedestal dig out and expose back of pedestal 2 ft. to 2-1/2 ft. open conduit aimed at center of pedestal 8 ft. of makeup wire 6 ft. maximum 5 ft. preferred 5 ft. minimum 2 in. schedule 80 PVC service entrance equipment 18 in. minimum icover to top iof conduit 24 in. trench depth bushing required, do not permanently attach to conduit 6 in. 3 in. schedule 40 PVC 3 in. to 2 in. schedule 40 reducer 24 in. radius, 2 in. schedule 40, 90 degree elbow Chapter 3: Underground Secondary Services / February 2010 13
(PAGE 42)
(PAGE 43)
(PAGE 44)
Meter Department Pre-Made Wire Bundles All are solid copper wire (PAGE 45) 1 Potentials #14 gauge Black, Green, White Currents #12 gauge Blue, Yellow, Brown 3 Potentials #14 gauge Black, Green, White, Orange Currents #12 gauge Blue, Yellow, Brown, Red Note: Maximum distance for #12 current wire is 35 feet one way to meet burden of 0.2 on rating factor 4 C.T. s. For C.T. conduit run over 35 feet use #10 current wire to a maximum of 60 feet for a burden of 0.2. If a longer conduit run than 60 feet is unavoidable see meter department for C.T. and burden chart s and C.T. sizing. DISTANCE CHART CT TO METER DISTANCE TOTAL W IRE DISTANCE SOLID STATE METER ADD ELECTRICAL MECHANICAL 0.01 0.05 0.002 <MISC> 0.002 0.009 <TEST SW> 0.009 #12 WIRE @.01588 OHM PER 10' 35' 50' 70' 70' 100' 140' 0.132 0.1798 0.243 0.17216 0.2198 0.28332 100' 200' 0.3386 0.3786 125' 250' 0.418 0.458 150' 300' 0.4974 0.5374 60' 120' 0.1408 0.1808 #10 WIRE @.009989 OHM PER 10' 75' 80' 100' 150' 160' 200' 0.1708 0.1808 0.2208 0.2108 0.2208 0.2608 200' 400' 0.4206 0.461
(PAGE 46)
(PAGE 47)
Clark Public Utilities Metering Requirements Commercial Applications (PAGE 48) Source Voltage Ampacity Reference Circle AW Part Number 120 Volts 1 2 Wire 120/240Volt 1 3Wire 120/240Volt 0-400 Amps 324N, 1 3Wire 324NF 120/240Volt Over 200 1 3Wire Amps 240/480Volt 1 3Wire 240/480Volt Over 200 1 3Wire Amps 120/208Volt 3Wire Network 120/208Volt Over 200 3Wire Network Amps 240Volt 3 3Wire Delta 120/208Volt 3 4Wire Wye 120/208Volt Over 200 3 4Wire Wye Amps 240/120Volt 3 4Wire Delta 240/120Volt Over 200 3 4Wire Delta Amps 277/480Volt 3 4Wire Wye 277/480Volt Over 200 3 4Wire Wye Amps 480Volt 3 3Wire Delta 480Volt 3 3Wire Delta Meter Diagram Numbers Circle AW part numbers are for cross reference only. All Commercial current transformer cabinets shall have hinged doors. CURRENT TRANSFORMER CABINET DIMENSIONS, Number of Terminals CT MOUNTING BASE Amperes Dimensions Circle AW or Equivalent 200 Amps- 400 Amps 1 24 X 30 X 11 6019-HAL (LUG LUG) 401 Amps- 800 Amps 1 30 X 36 X 11 6019-HEL (LUG LUG) 200 Amps- 400 Amps 3 30 X 36 X 11 6019-HAL or 6067-HAL 401 Amps- 800 Amps 3 36 X 48 X 11 6019-HEL or 6067-HEEL See EUSERC Spec 328B & 329B Over 800 Amps Switchgear Required Maximum wire size 600 MCM per lug or parallel per EUSERC SPEC. & UL label Rev 4: Changed blocks with a *. Bypass Provision Required 0-100 Amps U121314* MD01 4 Yes No 0-200 Amps U264 MD02 4 Yes No MD03 4 Yes No 12146 MD10 MD11 6 No Yes 0-200 Amps 124TB MD02 4 Yes No MD05 Dmd 12146 MD10 6 No Yes MD11 0-200 Amps 125TB MD04 5 Yes No 12148 MD12 8 No Yes 0-200 Amps 125TB MD06 5 Yes No 0-200 Amps 127TB MD07 7 Yes No 121413 MD13 13 No Yes 0-200 Amps 127TB MD08 7 Yes No 121413 MD14 13 No Yes 0-200 Amps 127TB MD07 7 Yes No 121413 MD13 13 No Yes 0-200 Amps 125TB MD06 5 Yes No Over 200 Amps 12148 MD12 8 No Yes Test Switch Required
Source Voltage Ampacity Reference Circle AW Part Number 120 Volts 1 2 Wire 120/240Volt 1 3Wire 120/240Volt 1 3Wire 0-400 Amps 324N, 120/240Volt 1 3Wire Clark Public Utilities Metering Requirements Residential Applications Meter Diagram Numbers Number of Terminals Bypass Provision Required 0-100 Amps 011 MD01 4 No No 0-200 Amps 204, U204 MD02 4 No No Over 400 Amps 324NF UO11, 011, 925 or 926 MD03 4 Yes No MD09 MD11A 5 or 6 No No Test Switch Required (PAGE 49) Circle AW part numbers are for cross reference only. CURRENT TRANSFORMER CABINET DIMENSIONS, CT MOUNTING BASE Amperes Dimensions Circle AW or Equivalent 200 Amps- 400 Amps 1 Window 24 h X 32 w X 9 d PED *401 Amps- 800 Amps 1 Buss Mt. 24 h X 30 w X 11 d hinged door 6019-HAL (LUG LUG) 200 Amps- 400 Amps 3 Window 30 h X 36 w X 11 d PED *401 Amps- 800 Amps 3 Buss Mt. 36 h X 48 w X 11 d hinged door 6019-HEL (LUG-LUG) * Optional Notes: 1. CT Metering for 200-400 Amp panels required pre-approval from Clark Public Utilities 2. All CT cans shall be mounted outside. Rev 2: Add optional CT cabinet dimensions and notes.
(PAGE 50) Clark Public Utilities Commercial Electric Service Handbook Figure 8 Typical 401 800 amp single-phase current transformer (CT) metering 30 in. wide conduit 35 ft. maximum permanent load and line identifying labels corresponding to appropriate connections Load Test Switch 36 in. tall Line 1 in. electrical conduit ground per NEC 6 ft. maximum 5 ft. preferred 5 ft. minimum hinged door required, hinges on opposite side of CT enclosure from meter socket ground per NEC 18 in. minimum 11 in. deep FINAL GRADE CT mounting base Installation requirements for current transformer mounting bases are as follows (Figure 9): Mounting base is rated for a minimum of 50k amps fault current. Line and load side terminations require two bolts per connector and two bolts on the neutral bus. The customer furnishes all lugs and terminates both load and line side conductors to the bus. A 4-wire delta service requires orange marking of the high leg. Switchboard metering Switchboard metering is required for three-phase services over 800 amps. At the customer s option, this type of metering may be installed for services sized 201 to 800 amps. The customer-installed equipment must be EUSERC-approved. Chapter 4: Commercial Metering / January 2011 33
(PAGE 51) Clark Public Utilities Commercial Electric Service Handbook Figure 9 Commercial three-phase CT mounting base 5 in. minimum two CT mounting bolts, 6 places typical 1-3/8 in. 7/8 in. 10 32 machine screw and washer drilled and tapped into bus N 1-1/2 in. 8-1/8 in. 1-3/8 in. CT CT CT 3/4 in. 7 in. minimum 7 in. minimum bus marking CT typical 3 locations insulating support 1/4 in. 3-5/16 in. insulating barrier NOTE: For additional information see EUSERC drawing 329B. All customer-installed switchboards require a: Current transformer (CT) mounting base. Service section. Set of bus bars/links. Panel(s). Meter base with provisions for a test switch. Means for locking the meter enclosure with independent 24-hour access to utility personnel. Concrete mounting pad. Case ground as required per the NEC. NOTE: Customers requiring more than 480 volts of service will have primary metering. Ownership and maintenance agreements for primary metered services will be mutually agreed upon with Clark Public Utilities. 34 Chapter 4: Commercial Metering / January 2011
(PAGE 52) Clark Public Utilities Commercial Electric Service Handbook Multiple metered services Commercial tenant spaces Non-residential multiple meter installations such as ganged, modular and switchboard metering have the following requirements: Spacing to socket centers a minimum of 3 feet and a maximum of 6 feet above the finished grade or the floor of an approved equipment room (factory-built meter packs require meters installed at least 3 feet above the ground). Meter packs with more than six meters require a main disconnect per the NEC (Figure 10). All self-contained meter bases require a safety socket or a manual link bypass. Each metered service is permanently labeled. (See Multiple meter labeling section for additional information.) Panel covers must be secured prior to connection of the service. Figure 10 Multiple meter socket detail meter and corresponding disconnect labeled with unit number using minimum 1/2 in. letters 7-1/2 in. min. hard plastic, metal or phenolic block labels with raised or engraved letters disconnect required if more than six meters Main disconnect 100 300 500 8-1/2 in. min. address label with minimum 1 in. letters 123 Clark St Bldg B service entrance 200 400 600 100 200 300 400 500 600 floor or finished grade 3 ft. min. 6 ft. max. HOUSE building meter labeled HOUSE with minimum 1/2 in. letters 6 ft. maximum 5 ft. preferred 5 ft. minimum NOTE: See page 31 for meter base bypass requirements. Chapter 4: Commercial Metering / January 2011 35
(PAGE 53)
(PAGE 54)
(PAGE 55)
(PAGE 56)
(PAGE 57)
(PAGE 58)
(PAGE 59)
(PAGE 60)
(PAGE 61)
(PAGE 62)
(PAGE 63)
(PAGE 64)
(PAGE 65)
(PAGE 66)