VA 26 23 00-2010 LOW-VOLTAGE SWITCHGEAR.pdf

1、09-10 26 23 00 - 1 SECTION 26 23 00 LOW-VOLTAGE SWITCHGEAR SPEC WRITER NOTE: This specification is not for general use. Use Section 26 24 11, DISTRIBUTION SWITCHBOARDS for most applications. Where justified, this specification may be used for main service entrance equipment (coordinate with Section

2、26 11 16, SECONDARY UNIT SUBSTATIONS). It should not be used for downstream levels of secondary distribution where switchboards would typically be used. Delete between / - / if not applicable to project. Also delete any other item or paragraph not applicable to the section and renumber the paragraph

3、s. PART 1 - GENERAL 1.1 DESCRIPTION This section specifies the furnishing, installation, and connection of the low voltage indoor switchgear. 1.2 RELATED WORK /A. Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS: Requirement for Seismic Restraint for Nonstructural Compo

4、nents./ B. Section 25 10 10, ADVANCED UTILITY METERING: Electricity meters installed in switchgear. C. Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS: General electrical requirements and items that are common to more than one section of Division 26. D. Section 26 05 21, LOW-VOLTAGE ELEC

5、TRICAL POWER CONDUCTORS AND CABLES (600 VOLTS AND BELOW): Cables and Wiring. E. 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. F. Section 26 05 33, RACEWAY AND BOXES FOR ELECTRICAL SYS

6、TEMS: Conduit and outlet boxes. G. Section 26 05 71, ELECTRICAL SYSTEM PROTECTIVE DEVICE STUDY: Coordination study of overcurrent protection devices. H. Section 26 11 16, SECONDARY UNIT SUBSTATIONS: Secondary unit substation. Provided by IHSNot for ResaleNo reproduction or networking permitted witho

7、ut license from IHS-,-,-09-10 26 23 00 - 2 /I. Section 26 13 13, GENERATOR PARALLELING CONTROLS: For generator paralleling controls./ J. Section 26 25 11, BUSWAYS: Feeder Busways and Fittings. K. Section 26 43 13, TRANSIENT-VOLTAGE SURGE SUPPRESSION: For TVSS units integral to the switchgear. 1.3 QU

8、ALITY ASSURANCE Refer to Paragraph, QUALIFICATIONS, in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS. 1.4 FACTORY TESTS A. Low-voltage switchgear shall be thoroughly tested at the factory to assure that there are no electrical or mechanical defects. Tests shall be conducted as per UL a

9、nd ANSI Standards. Factory tests shall be certified. B. Thoroughly test the switchgear at the factory with the circuit breakers in the connected position in their cubicles. The factory tests shall be in accordance with C37.20 and ANSI C37.51 and shall include the following tests: 1. Design Tests 2.

10、Production Tests 3. Conformance Tests C. The following additional tests shall be performed: 1. Verify that circuit breaker sizes and types correspond to drawings and coordination study. 2. Verify tightness of bolted electrical connections by calibrated torque-wrench method in accordance with manufac

11、turers published data. 3. Confirm correct operation and sequencing of electrical and mechanical interlock systems by attempting closure on locked-open devices, and attempting to open locked-closed devices, and making key exchange with devices operated in off-normal positions. 4. Verify correct barri

12、er and shutter installation and operation. 5. Exercise all active components. 6. Inspect indicating devices for correct operation. 7. Perform a dielectric withstand voltage test on each bus section, each phase-to-ground with phases not under test grounded, in accordance with manufacturers published

13、data. 8. Perform insulation-resistance tests on control wiring with respect to ground. Applied potential shall be 500 volts dc for 300-volt Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 23 00 - 3 rated cable and 1000 volts dc for 600-volt

14、rated cable, or as required if solid-state components or control devices cannot tolerate the applied voltage. 9. If applicable, verify correct function of control transfer relays located in the switchgear with multiple control power sources. 10. Perform phasing checks on double-ended or dual-source

15、switchgear to insure correct bus phasing from each source. D. Furnish four (4) copies of certified manufacturers factory test reports to the Resident Engineer prior to shipment of the switchgear to ensure that the switchgear has been successfully tested as specified. SPEC WRITER NOTE: Determine if w

16、itness testing is a VA requirement. Edit or remove paragraph to conform to project requirements. /E. The Government shall have an option to witness the factory tests. All expenses of the Government Representatives trips to witness the testing will be paid by the Government. Notify the Resident Engin

17、eer not less than 30 days prior to making tests at the factory./ 1.5 SUBMITTALS A. Submit in accordance with Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS: B. Shop Drawings: 1. Sufficient information, clearly presented, shall be included to determine compliance with drawings and specif

18、ications. 2. Include electrical ratings, dimensions, mounting details, materials, required clearances, terminations, weight, 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

19、time, instantaneous and ground fault settings, coordinated breaker and fuse curves, accessories, 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. C. Manual

20、s: 1. Submit, simultaneously with the shop drawings, companion copies of complete maintenance and operating manuals including technical data sheets, wiring diagrams, and information for ordering replacement parts. Provided by IHSNot for ResaleNo reproduction or networking permitted without license f

21、rom IHS-,-,-09-10 26 23 00 - 4 a. Wiring diagrams shall have their terminals identified to facilitate installation, maintenance, and operation. b. Wiring diagrams shall indicate internal wiring for each item of equipment and the interconnection between the items of equipment. c. Provide a clear and

22、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 drawings. 2. Two weeks prior to final inspection, deliver four copies of the final updated maintenanc

23、e 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 shall be included which show all items of equipment and their interconnecting wiring. c. Show a

24、ll terminal identification. d. Include information for testing, repair, trouble shooting, assembly, disassembly, and factory recommended/required periodic maintenance procedures and frequency. e. Provide a replacement and spare parts list. Include a list of tools and instruments for testing and main

25、tenance purposes. f. Furnish manuals in loose-leaf binder or manufacturers standard binder. D. Certifications: 1. Two weeks prior to final inspection, submit four copies of the following to the /Resident Engineer/ /COTR/: a. Certification by the Contractor that the assemblies have been properly inst

26、alled, adjusted and tested, including circuit breaker settings. b. Certified copies of all of the factory design and production tests, field test data sheets and reports for the assemblies. 1.6 APPLICABLE PUBLICATIONS A. Publications listed below (including amendments, addenda, revisions, supplement

27、s, and errata), form a part of this specification to the extent referenced. Publications are referenced in the text by basic designation only. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 23 00 - 5 B. Institute of Engineering and Electron

28、ic Engineers (IEEE): C37.13 . Low Voltage AC Power Circuit Breakers Used in Enclosures C37.20.1 . Standard for Metal-Enclosed Low-Voltage Power Circuit-Breaker Switchgear C57.13 . Instrument Transformers C62.41 . Surge Voltage in Low Voltage AC Power Circuits C. National Electrical Manufacturers Ass

29、ociation (NEMA): SG-3 . Low Voltage Power Circuit Breakers. SG-5 . Power Switchgear Assemblies. D. National Fire Protection Association (NFPA): 70 . National Electrical Code (NEC). E. Underwriters Laboratories, Inc. (UL): UL 891 Dead-Front Switchboards 977 Safety Fused Power Circuit Devices 1053 . G

30、round Fault Sensing and Relaying Equipment UL 1558 Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear PART 2 - PRODUCTS 2.1 GENERAL A. Low voltage switchgear shall be in accordance with IEEE, NEMA, NFPA and UL. B. Provide complete switchgear including, but not limited to housing, buses, dra

31、w out air circuit breakers, instruments and related transformers, relays fuses and wiring. C. Switchgear dimensions shall not exceed the dimensions shown on the drawings. D. Manufacturers nameplate shall include complete ratings of switchgear in addition to date of manufacture. 2.2 HOUSING A. Constr

32、uction: Provide housing of structural or formed steel frame braced to maintain alignment and resist damage during shipment, erection, and by stresses resulting from short circuits. Enclose the frame on all sides, top, and bottom (except cable compartment) with sheet steel covers, doors and panels an

33、d equip with interior barriers. Provide rear access panels of the hinged type with provisions for padlocking. Provide ventilating louvers where required to limit the temperature rise of current carrying parts. Provide breakers with Provided by IHSNot for ResaleNo reproduction or networking permitted

34、 without license from IHS-,-,-09-10 26 23 00 - 6 hinged covers and cutouts for control mechanism. Protect all openings against entrance of falling dirt, water or foreign matter. Isolate each breaker in its own compartment. Metering transformers and instruments shall be similarly isolated. B. Paintin

35、g: Enclosure shall be thoroughly cleaned, phosphate treated and primed by a phosphate or similar treatment, and followed immediately with a rust-inhibiting paint. Final finish coat shall be the manufacturers standard gray. C. Breaker Compartments: The breaker compartments shall include stationary pr

36、imary contacts, stationary secondary contacts as required, barriers, and rails for the drawout elements. SPEC WRITER NOTE: Include the following paragraphs and items only as required. /D. Auxiliary Compartments: Match and align with basic switchgear assembly. Include the following: 1. Utility meteri

37、ng compartment that complies with utility company requirements. 2. Bus transition sections. 3. Incoming-line pull sections. 4. Hinged front panels for access to metering, accessory, and blank compartments. 5. Pull box on top of switchgear for extra room for pulling cable, with removable top, front,

38、and side covers and ventilation provisions adequate to maintain air temperature in pull box within same limits as switchgear. a. Set pull box back from front to clear circuit-breaker lifting mechanism. b. Bottom: Insulating, fire-resistant material with separate holes for cable drops into switchgear

39、 c. Cable Supports: Arranged to ease cabling and adequate to support cables indicated, including those for future installation./ /E. Heaters: Provide 120-volt heaters in each switchgear section. Heaters shall be of sufficient capacity to control moisture condensation in the section, shall be 250 wa

40、tts minimum, and shall be controlled by a thermostat /and humidistat/ located in the section. Thermostat shall be industrial type, high limit, to maintain sections within the range of 15 to 32 degrees C (60 to 90 degrees F) 60 to 90 degrees F. Humidistat shall have a range of 30 to 60 percent relati

41、ve humidity. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 23 00 - 7 Supply voltage for the heaters shall be obtained from a control power transformer within the switchgear. If heater voltage is different than switchboard voltage, provide

42、transformer rated to carry 125 percent of heater full load rating. Transformer shall have 220 degrees C insulation system with a temperature rise not exceeding 115 degrees C and shall conform to NEMA ST 20./ /F. Louvers equipped with insect and rodent screen and filter; arranged to permit air circul

43、ation while excluding insects, rodents, and exterior dust./ 2.3 BUSES A. General: Arrange buses for 3 phase, 4 wire distribution. The phase buses (through bus), neutral bus, and ground bus shall be full capacity and shall extend the entire length of the switchgear. Make provisions for future extensi

44、ons by means of bolt holes or other approved method. Brace bus to withstand short circuit current available at the particular location. B. Material and Size: Buses and connections shall be hard-drawn copper of 98 percent conductivity. Bus size and arrangement shall be such that the temperature rise

45、of the buses shall not exceed IEEE standards. Bus connections to circuit breakers shall be copper. Size feeder busing to the line side of breakers based on IEEE. Bus laminations shall have a minimum of 1/4 inch 6mm spacing. C. Bus Connections: Provide bolted or welded connections. All contact surfac

46、es are of copper. A minimum of two plated bolts per splice or connection is required for nonwelded bus except where physical bus size permits only one bolt; the joint shall include an approved means, other than friction, to prevent turning, twisting, or bending. Bolts shall be torqued to the values

47、recommended by the manufacturer. D. Neutral Bus: Provide bare neutral bus mounted on insulated bus supports. Provide neutral disconnect links to permit isolation of the neutral bus from the common ground bus and service entrance conductors. E. Ground Bus: Provide an uninsulated 6 mm by 50 mm (1/4 in

48、ch by 2 inch) copper equipment ground bus bar the length of the switchgear and secure to each unit frame. F. Main Bonding Jumper: An uninsulated 6 mm by 50 mm (1/4 inch by 2 inch) copper bus shall interconnect the neutral and ground buses, when the secondary service equipment is incorporated within

49、the switchgear to establish the system common ground point. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 23 00 - 8 2.4 NAMEPLATES AND MIMIC BUS 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 ci