VA 26 24 11-2009 DISTRIBUTION SWITCHBOARDS.pdf

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1、4-09 26 24 11 - 1 SECTION 26 24 11 DISTRIBUTION SWITCHBOARDS SPEC WRITER NOTE: Delete between / - / if not applicable to project. Also delete any other item or paragraph not applicable to the section and renumber the paragraphs. Use this section for individual switchboards or in conjunction with Sec

2、tion 26 11 16, SECONDARY UNIT SUBSTATIONS. PART 1 - GENERAL 1.1 DESCRIPTION This section specifies the furnishing, installation, and connection of the distribution switchboards. 1.2 RELATED WORK /A. Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS: Requirements for Seis

3、mic Restraint for Nonstructural Components./ B. Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS: General electrical requirements and items that are common to more than one section of Division 26. C. Section 26 05 21, LOW-VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES (600 VOLTS AND BELOW

4、): Cables and wiring. D. Section 26 05 26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS: Requirements for Personnel Safety and to provide a low impedance path for possible fault currents. E. Section 26 05 33, RACEWAY AND BOXES FOR ELECTRICAL SYSTEMS: Conduit and outlet boxes. F. Section 26 05 71, EL

5、ECTRICAL SYSTEM PROTECTIVE DEVICE STUDY: Coordination study of overcurrent protection devices. G. Section 26 09 13, ELECTRICAL POWER MONITORING AND CONTROL: For metering devices integral to the distribution switchboards. H. Section 26 11 16, SECONDARY UNIT SUBSTATIONS: Switchboards as part of second

6、ary unit substation. I. Section 26 25 11, BUSWAYS: Feeder busway and fittings. /J. Section 26 27 13, ELECTRIC METERING: For revenue metering devices integral to the distribution switchboards./ K. Section 26 43 13, TRANSIENT-VOLTAGE SURGE SUPPRESSION: TVSS equipment for distribution switchboards. 1.3

7、 QUALITY ASSURANCE Refer to Paragraph, QUALIFICATIONS, in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-09 26 24 11 - 2 1.4 FACTORY TESTS A. Distribution switchboards shall be thoroughl

8、y tested at the factory to assure that there are no electrical or mechanical defects. Tests shall be conducted as per NEMA PB 2 and UL 891. Factory tests shall be certified. B. The following additional tests shall be performed: 1. Verify that circuit breaker sizes and types correspond to drawings an

9、d coordination study. 2. Verify tightness of bolted electrical connections by calibrated torque-wrench method in accordance with manufacturers published data. /3. Confirm correct operation and sequencing of electrical and mechanical interlock systems by attempting closure on locked-open devices, and

10、 attempting to open locked-closed devices, and making key exchange with devices operated in off-normal positions./ 4. Exercise all active components. 5. Perform a dielectric withstand voltage test on each bus section, each phase-to-ground with phases not under test grounded, in accordance with manuf

11、acturers published data. 6. Perform insulation-resistance tests on control wiring with respect to ground. Applied potential shall be 500 volts dc for 300-volt rated cable and 1000 volts dc for 600-volt rated cable, or as required if solid-state components or control devices cannot tolerate the appli

12、ed voltage. 7. If applicable, verify correct function of control transfer relays located in the switchboard with multiple control power sources. 8. Perform phasing checks on double-ended or dual-source switchboards to insure correct bus phasing from each source. C. Furnish four (4) copies of certifi

13、ed manufacturers factory test reports to the Resident Engineer prior to shipment of the switchboards to ensure that the switchboards have been successfully tested as specified. /D. The Government shall have an option to witness the factory tests. All expenses of the Government Representatives trips

14、to witness the testing will be paid by the Government. Notify the Resident Engineer not less than 30 days prior to making tests at the factory./ 1.5 SUBMITTALS Submit in accordance with Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS: A. Shop Drawings: 1. Sufficient information, clearly

15、presented, shall be included to determine compliance with drawings and specifications. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-09 26 24 11 - 3 2. Include electrical ratings, dimensions, mounting details, materials, required clearances, term

16、inations, weight, temperature rise, wiring and connection diagrams, plan, front, side, and rear elevations, sectional views, bus work, circuit breaker frame sizes, trip and short-circuit rating, long-time, short-time, instantaneous and ground fault settings, coordinated breaker and fuse curves, acce

17、ssories, and device nameplate data. 3. Show the size, ampere-rating, number of bars per phase and neutral in each bus run (horizontal and vertical), bus spacing, equipment ground bus, and bus material. B. Manuals: 1. Submit, simultaneously with the shop drawings, companion copies of complete mainten

18、ance and operating manuals including technical data sheets, wiring diagrams, and information for ordering replacement parts. a. Wiring diagrams shall have their terminals identified to facilitate installation, maintenance, and operation. b. Wiring diagrams shall indicate internal wiring for each ite

19、m of equipment and the interconnection between the items of equipment. c. Provide a clear and concise description of operation, which gives, in detail, the information required to properly operate the equipment. d. Approvals will be based on complete submissions of manuals together with shop drawing

20、s. 2. Two weeks prior to final inspection, deliver four copies of the final updated maintenance and operating manuals to the Resident Engineer. a. The manuals shall be updated to include any information necessitated by shop drawing approval. b. Complete “As Installed“ wiring and schematic diagrams s

21、hall be included which show all items of equipment and their interconnecting wiring. c. Show all terminal identification. d. Include information for testing, repair, trouble shooting, assembly, disassembly, and recommended maintenance intervals. e. Provide a replacement parts list with current price

22、s. Include a list of recommended spare parts, tools, and instruments for testing and maintenance purposes. f. Furnish manuals in loose-leaf binder or manufacturers standard binder. C. Certifications: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-

23、09 26 24 11 - 4 1. Two weeks prior to final inspection, submit four copies of the following to the Resident Engineer: a. Certification by the Contractor that the assemblies have been properly installed, adjusted and tested, including circuit breakers settings. b. Certified copies of all of the facto

24、ry design and production tests, field test data sheets and reports for the assemblies. 1.6 APPLICABLE PUBLICATIONS Publications listed below (including amendments, addenda, revisions, supplements and errata) form a part of this specification to the extent referenced. Publications are referenced in t

25、he text by basic designation only. A. Institute of Engineering and Electronic Engineers (IEEE): C37.13 . Low Voltage AC Power Circuit Breakers Used in Enclosures C57.13 . Instrument Transformers C62.41 . Surge Voltage in Low Voltage AC Power Circuits C62.45 . Surge Testing for Equipment connected to

26、 Low-Voltage AC Power Circuits B. National Electrical Manufacturers Association (NEMA): PB-2 . Dead-Front Distribution Switchboards. PB-2.1 . Instructions for Proper Handling, Installation, Operation, and Maintenance of Switchboards AB-1 . Molded Case Circuit Breakers, Molded Case Switches and Circu

27、it Breaker Enclosures C. National Fire Protection Association (NFPA): 70 . National Electrical Code (NEC) D. Underwriters Laboratories, Inc. (UL): 67 . Panelboards 489 Molded Case Circuit Breakers and Circuit Breakers Enclosures 891 Dead-Front Switchboards 1283 . Electromagnetic Interference Filters

28、 1449 . Transient Voltage Surge Suppressors PART 2 - PRODUCTS 2.1 GENERAL A. Switchboards shall be in accordance with UL, NEMA, NEC, IEEE, and as shown on the drawings. B. Switchboards shall be provided complete, ready for operation including, but not limited to housing, buses, circuit breakers, ins

29、truments and related transformers, fuses, and wiring. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-09 26 24 11 - 5 C. Switchboard dimensions shall not exceed the dimensions shown on the drawings. D. Manufacturers nameplate shall include complete

30、 ratings of switchboard in addition to the date of manufacture. SPEC WRITER NOTE: Select the Type I or Type II switchboard as required for the particular project. Based on the short circuit and coordination study for the project use fully rated circuit breakers. 2.2 BASIC ARRANGEMENT A. Type I: Swit

31、chboard shall be front accessible with the following features: 1. Device mounting: a. Main breaker: Individually mounted and compartmented or group mounted with feeder breakers. b. Feeder breakers: Group mounted. 2. Section alignment: As shown on the drawings. 3. Accessibility: a. Main section line

32、and load terminals: Front and side. b. Distribution section line and load terminals: Front. c. Through bus connections: Front and end. 4. Bolted line and load connections. 5. Full height wiring gutter covers for access to wiring terminals. SPEC WRITER NOTE: Fill in the short circuit ratings required

33、 below. 6. Short Circuit Current Rating: / _ / amperes rms symmetrical, minimum, or as shown on the drawings, whichever is higher. B. Type II: Switchboard shall be rear accessible with the following features: 1. Device mounting: a. Main breaker: Individually mounted and compartmented. b. Feeder brea

34、kers: Individually mounted and compartmented. 2. Section alignment: As shown on drawings. 3. Accessibility: a. Main section line and load terminals: Rear. b. Distribution section line and load terminals: Rear. c. Bus connections: Rear. SPEC WRITER NOTE: Fill in the short circuit rating required belo

35、w. 4. Short Circuit Current Rating: / _ / amperes rms symmetrical, minimum, or as shown on the drawings, whichever is higher. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-09 26 24 11 - 6 2.3 HOUSING A. Provide a completely enclosed, free standin

36、g, steel enclosure not less than the gage required by the ANSI and UL standards. The enclosure is to consist of the required number of vertical sections bolted together to form one metal enclosed rigid switchboard. The sides, top and rear shall be covered with removable screw on sheet steel plates.

37、B. Provide ventilating louvers where required to limit the temperature rise of current carrying parts. All openings shall be protected against entrance of falling dirt, water, or foreign matter. C. Enclosure shall be thoroughly cleaned, phosphate treated, and primed with rust-inhibiting paint. Final

38、 finish coat to be the manufacturers standard gray. Provide a quart of finish paint for touch-up purposes. 2.4 BUSES A. General: Buses shall be arranged for 3 phase, 4 wire distribution. Main phase buses (through bus), full size neutral bus, and ground bus shall be full capacity the entire length of

39、 the switchboard. Provide for future extensions by means of bolt holes or other approved method. Brace the bus to withstand the available short circuit current at the particular location and as shown on the drawings. No magnetic material shall be used between buses to form a magnetic loop. B. Materi

40、al and Size: Buses and connections shall be hard drawn copper of 98 percent conductivity. Bus temperature rise shall not exceed 65 degrees C (149 degrees F). Section busing shall be sized based on UL and NEMA Switchboard Standards. C. Bus Connections: All contact surfaces shall be copper. Provide a

41、minimum of two plated bolts per splice. Where physical bus size permits only one bolt, provide a means other than friction to prevent turning, twisting or bending. Torque bolts to the manufacturers recommended values. D. Neutral Bus: Provide bare or plated bus and mount on insulated bus supports. Pr

42、ovide neutral disconnect link to permit isolation of neutral bus from the common ground bus and service entrance conductors. E. Ground Bus: Provide an uninsulated 6 mm by 50 mm (1/4 inch by 2 inch) copper equipment ground bus bar sized per UL 891 the length of the switchboard and secure at each sect

43、ion. SPEC WRITER NOTE: Include paragraph F only if the neutral is to be grounded at this point. /F. Main Bonding Jumper: Connect an uninsulated 1/4 inch by 2 inch (6mm by 50 mm) copper bus between the neutral and ground buses to establish the system common ground point./ Provided by IHSNot for Resal

44、eNo reproduction or networking permitted without license from IHS-,-,-4-09 26 24 11 - 7 2.5 TRANSIENT VOLTAGE SURGE SUPPRESSION Refer to Section 26 43 13, TRANSIENT-VOLTAGE SURGE SUPPRESSION. 2.6 METERING Refer to Section 26 09 13, ELECTRICAL POWER MONITORING AND CONTOL. 2.7 NAMEPLATES AND MIMIC BUS

45、 A. Nameplates: For Normal Power system, provide laminated black phenolic resin with white core with 1/2 inch 12mm engraved lettered nameplates next to each circuit breaker. For Essential Electrical System, provide laminated red phenolic resin with white core with 1/2 inch 12mm engraved lettered nam

46、eplates next to each circuit breaker. Nameplates shall indicate equipment served, spaces, or spares in accordance with one line diagram shown on drawings. Nameplates shall be mounted with plated screws on front of breakers or on equipment enclosure next to breakers. Mounting nameplates only with adh

47、esive is not acceptable. B. Mimic Bus: Provide an approved mimic bus on front of each switchboard assembly. Color shall be black for the Normal Power system and red for the Essential Electrical System, either factory-painted plastic or metal strips. Plastic tape shall not be used. Use symbols simila

48、r to one line diagram shown on drawings. Plastic or metal strips shall be mounted with plated screws. 2.8 PROVISION FOR FUTURE Where “provision for“, “future“, or “space“ is noted on drawings, the space shall be equipped with bus connections to the future overcurrent device with suitable insulation

49、and bracing to maintain proper short circuit rating and physical clearance. Provide buses for the ampere rating as shown for the future device. 2.9 BREAKER REMOVAL EQUIPMENT Where draw out circuit breakers are provided, furnish a portable elevating carriage or switchboard permanent top mounted device for installation and removal of the breakers. 2.10 CONTROL WIRING Control wiring sh