SECTION 16425 SWITCHBOARD PART 1 GENERAL 1.01 SUMMARY A. Related Section: 1. 16450 - Grounding. 1.02 SUBMITTALS A. Submit manufacturer's literature and technical data before starting work. B. Submit Shop Drawings for switchboard: 1. Include dimensioned outline drawings, front elevation with location and identification of devices and instruments, bus duct connection details, conduit entrance locations, mounting and leveling instructions, device ratings and characteristics, main bus construction and location, main device key interlock details, ground fault connection diagram, and other details of construction. 2. Submit time-current coordination curves of main tie and feeder devices. 3. Include details of the service bus ducts, including dimensioned outline drawings, ratings, and installation details. C. Submit nameplate schedule for review. 1.03 QUALITY ASSURANCE A. Regulatory Requirement: 1987 NEC - Article 384. PART 2 PRODUCTS 2.01 MANUFACTURERS A. Bus Ducts: 1. Westinghouse Pow-R-Way. 2. Challenger Electrical Equipment Corp. 3. Siemens. 4. Square D. Project No. SPECIFICATION GUIDELINES 16425-1
2.02 INSTALLATION A. Furnish and install where indicated a dead front type, completely metal enclosed, self-supporting structure independent of wall supports, consisting of the required number of vertical sections bolted together to form one rigid switchboard 90-3/8" high. The sides and rear shall be covered with removable screw-on plates. Edges of front covers or hinged front panels shall be formed. Voltage rating shall be as indicated on the drawings. B. Equipment shall comply with the latest applicable standards of NEMA, ANSI, and UL. The switchboard shall be labeled for service entrance equipment. C. Small wiring, necessary fuse blocks, and terminal blocks within the switchboard shall be furnished as required. Groups of control wires leaving the switchboard shall be provided with terminal blocks with suitable numbering strips. D. Switchboard shall be provided with adequate lifting means and shall be capable of being rolled or moved into installation position and bolted directly to the floor without the use of floor sills. E. Exterior and interior steel surfaces of the switchboard shall be properly cleaned and finished with gray enamel over a rust-inhibiting phosphatic coating. Color shall be ANSI 61 gray. F. Engraved Nameplates: 1. Furnish for main and feeder circuits including control fuses and for indicating lights and instruments. 2. Nameplates shall give item designation, circuit number, frame ampere size, and appropriate trip rating. 3. Provide "Main Switch" nameplates. 4. Furnish Master Nameplate giving switchboard designation, voltage, ampere rating, short circuit rating, manufacturer's name, general order number, and item number. G. Bus Bars: 1. Bus Bars shall be copper. 2. Bus work shall be rated to withstand maximum short circuit stresses when connected to a supply system having fault capacity as determined by the short Project No. SPECIFICATION GUIDELINES 16425-2
circuit study on the electrical system in the worst contingency of amps symmetrical at rated voltage. 3. Main horizontal bus bars shall be mounted with all three phases arranged in the same vertical plane. 4. Provide full capacity neutral where a neutral is indicated on the drawings. 5. A ground bus and lug shall be furnished firmly secured to each vertical section structure and shall extend the entire length of the switchboard. 6. Provide ground lugs for each overcurrent device in the switchboard. 7. Hardware used on conductors shall be high-tensile strength and zinc plated. 8. Terminals shall be of the anti-turn solderless type suitable for CU or AL cable of sizes indicated. H. Furnish cable pull sections or top cable pull boxes where shown on the drawings complete with cable tie down supports. Where cable pull section or pull boxes contain utility service cables provide utility acceptable sealing means. I. Where spaces are indicated on the drawings, provide fully bussed sections ready to receive circuit breakers. J. Switchboard Type (Front-Accessible Panel-Mounted): 1. Switchboards shown mounted against a wall shall be of construction equal to Westinghouse WF or accepted equivalent. All sections of the switchboard shall be 20 inches deep except deeper service sections containing large ampacity main disconnects. Sections of the switchboard shall align so the back of the complete structure may be placed flush against a wall. 2. Construction shall allow maintenance of incoming line terminations, main device connections, and main bus bolted connections to be performed without rear access. The feeder or branch devices shall be removable from the front and shall be panel mounted with the necessary device line and load connection front accessible. K. Overcurrent Protective Devices: 1. Main Circuit Breakers: a. Main protective devices shall be encased Westinghouse Systems Pow-R-Breakers, Type SPB or accepted equivalent. 1) Breakers shall be UL listed for application in Project No. SPECIFICATION GUIDELINES 16425-3
their intended enclosure for 100 percent of their continuous ampere rating. 2) Frame ampere ratings shall be as shown on the drawings. Breakers shall have an interrupting capacity as determined by the short circuit study on the electrical system in the worst contingency and shall be rated ka RMS symmetrical interrupting capacity at rated voltage and RMS symmetrical short time rating as indicated. b. Provide plug-in Pow-R Trip 7 trip devices that are interchangeable between compatible breaker frames. 1) Suitable interlocking shall be provided between Pow-R Trip 7 trip devices and related frames to ensure correct application. 2) The continuous ampere rating of the breaker shall be determined by the insertion of an interchangeable rating plug that matches the load and cable requirements. 3) The rating plug shall be interlocked with the tripping mechanism to automatically "open" the breaker when the plug is removed. 4) The breaker shall remain "trip free" with the plug removed. 5) Rating plugs shall be keyed to prevent incorrect application between different frame ratings. c. Complete system selective coordination shall be provided by the addition of the following time/ current curve shaping adjustments: 1) Ampere Setting. 2) Long Time Delay. 3) Short Time Pick-Up (Only Mains) (Only Tie) (Only Feeders). 4) Short Time Delay. 5) Ground Fault Pick-Up, if applicable per NEC. 6) Ground Fault Time Delay, if applicable per NEC. d. Ground Fault Trip, when required by NEC: 1) Provide as an integral part of the breaker. 2) The ground fault pickup shall be adjustable with a maximum setting of 1200 amps according to the NEC. 3) The time delay shall be adjustable in three discrete bands for maximum system selective Project No. SPECIFICATION GUIDELINES 16425-4
coordination. 4) A memory circuit shall be provided to compensate for the erratic nature of arcing ground faults to provide for positive tripping actions. 5) A residual scheme shall be used as standard for detecting ground fault currents. e. A separately mounted test panel shall be provided for use with Pow-R Trip 7 trip devices. The test panel shall test the ground fault circuit in one of two methods. 1) By tripping the breaker. 2) By not tripping the breaker. 2. Feeder Circuit Breakers: a. Main and Feeder Protective Devices: Molded case air circuit breakers, built, tested, and UL labeled according to UL 489. b. Breakers 100 through 400 amperes: Frame shall be thermal-magnetic trip with inverse time current characteristics. c. Breakers 225 through 400 amperes: Provide continuously adjustable magnetic pickups of approximately five to ten times trip rating. d. Breakers 600 amperes frame and above: With solidstate trip complete with built in current transformers, solid-state trip unit, and flush transfer shunt trip, by Westinghouse Seltronic or accepted equivalent. 1) Breakers shall have easily changed trip rating plugs with trip ratings as indicated on drawings. 2) Rating plugs shall be interlocked so they are not interchangeable between frames. When interlocked, the breaker cannot be latched with rating plug removed. 3) Breaker shall have built-in test points for testing long delay and instantaneous and ground fault, where shown, functions of the breaker by means of a 120 volt operated test kit. 4) Provide one test kit capable of testing breakers 600 amperes and above. 5) Solid-state instantaneous element shall be continuously adjustable from approximately 4 to 8 times the trip rating, with short time adjustment from instantaneous to 10 cycle delay Project No. SPECIFICATION GUIDELINES 16425-5
L. Meters: for coordination purposes. 6) Provide short delay override feature providing for instantaneous tripping on high magnitude faults. e. Where indicated on Drawings, provide optional adjustable trip rating plug approximately 70 to 100 percent of trip rating. Molded case breakers shall be determined by the short circuit study on the electrical system in the worst contingency and have a minimum ka symmetrical RMS interrupting capacity at rated voltage. 1. 250 degrees, 7.1 inch scale, rectangular front connected switchboard type with accuracy of +1 percent shielded. 2. Provide following customer metering equipment: a. Three single pole fuse blocks with current limiting fuses. b. One voltmeter phase selector switch, sevenposition. c. One voltmeter, 0-system volts. d. One ammeter phase selector switch, four-position. e. One ammeter, scale as indicated. M. Service Bus Ducts: 1. Service bus ducts shall be in a steel housing, with individual bus bars insulated and supported over their entire lengths. Bars shall be copper silver plated at joints with at least 2 bolts per joint. Joint clamping bolts shall be "cold" and accessible for tightening at all times. 2. Vault stubs shall be constructed according to utility company standards. Coordinate location of stubs into vault with utility company. 3. Bus duct rating shall be of voltage and amperage as indicated, three-phase, four-wire. The bus duct rating shall be determined by the short circuit study on the electrical system in the worst contingency and shall be braced for the maximum available fault, in symmetrical amperes. N. Provide lightning and surge protection. PART 3 EXECUTION Project No. SPECIFICATION GUIDELINES 16425-6
3.01 INSPECTION A. Do not proceed with the work of this section until conditions detrimental to the proper and timely completion of the work have been corrected in an acceptable manner. 3.02 INSTALLATION A. Provide adequate and safe storage space for the switchboard when received from the factory. Follow handling and storage instructions provided by the manufacturer. Store in a clean, dry place while awaiting installation. B. Refer to the installation drawings furnished by the manufacturer to coordinate alignment and connection of service bus ducts and locations of conduit entry. Conduits shown on the floor slab and turning up under the bottom of the switchboard are not to be installed until final approved Shop Drawings are received, in order to coordinate conduit locations with openings in the bottom of the switchboard. This also applies to grounding cable turning up into the bottom of the switchboard. C. Steel conduits turning up under the bottom of the switchboard shall each be provided with a steel grounding bushing, connected to the switchboard ground bus with a stranded copper conductor sized according to Table 250-95 of the NEC. This shall also apply to steel conduits entering the switchboard from the top. Non-metallic duct entering the switchboard from the bottom shall each contain a stranded, THW copper bonding conductor, sized according to Table 250-95 of the NEC that shall be connected to the switchboard ground bus. Connections of bond wires to the switchboard ground bus shall be made with bolted compression lugs. D. The metal frame of the switchboard shall be connected to the switchboard ground bus, in at least 2 places, with stranded copper conductors of minimum 3/0 size. E. The switchboard shall be installed on a 4 inch high concrete pad. F. Each device in the switchboard shall have a black and white laminated plastic nameplate, of dimensions and wording as shown on the drawings. G. After the switchboard is completely installed, but before energizing, the floor under the switchboard and the floor Project No. SPECIFICATION GUIDELINES 16425-7
throughout the main switchgear room, shall be thoroughly cleaned. Remove dust, dirt, and debris. Thoroughly clean outside of switchboard including the top. Any factory paint damaged before, during, or after installation shall be repainted or touched up with same type and color paint. H. Service bus ducts shall be installed from the utility company vault, through the wall and turn down into the top of the switchboard as detailed on drawings. Provide fire stop on each side of the wall around each bus duct. Provide careful alignment of the bus bars of the bus duct with the main bus of the switchboard. Insure the metal enclosure of each service bus duct is bonded to the metal enclosure of the switchboard. Fully coordinate, with utility company, proper phasing of bus bars in switchboard to comply with the NEC. 3.03 FIELD QUALITY CONTROL A. Manufacturer's Field Service: A minimum of 1 day of manufacturer's factory engineering service shall be provided to lend technical assistance in setting circuit breaker trip settings. These settings shall include but not be limited to: 1. Ground Fault Setting 2. Long Time Trip END OF SECTION Project No. SPECIFICATION GUIDELINES 16425-8