262300 Switchgear.pdf

11-01-22

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SECTION 26 23 00

LOW-VOLTAGE SWITCHGEAR

PART 1 - GENERAL

1.1 DESCRIPTION

A. This section specifies the furnishing, installation, connection, and testing of low-voltage switchgear, indicated as switchgear in this section.

1.2 RELATED WORK

A. Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS:

Requirements that apply to all sections of Division 26.

B. Section 26 05 73, OVERCURRENT PROTECTIVE DEVICE COORDINATION STUDY:

Short circuit and coordination study, and requirements for a coordinated electrical system.

1.3 QUALITY ASSURANCE

A. Quality Assurance shall be in accordance with Paragraph, QUALIFICATIONS

(PRODUCTS AND SERVICES) in Section 26 05 11, REQUIREMENTS FOR

ELECTRICAL INSTALLATIONS.

1.4 FACTORY TESTS

A. Factory Tests shall be required.

B. Factory Tests shall be in accordance with Paragraph, MANUFACTURED

PRODUCTS in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL

INSTALLATIONS, and the following requirements:

C. Switchgear shall be tested, with the circuit breakers in the connected position in their compartments. Tests shall be in accordance with IEEE

C37.20.1 and NEMA C37.51. Factory tests shall be certified, and shall include the following tests:

1. Design tests.

2. Production tests.

3. Conformance tests.

D. The following additional tests shall be performed:

1. Verify that circuit breaker sizes and types correspond to drawings, and the Overcurrent Protective Device Coordination Study.

2. Verify tightness of bolted electrical connections by calibrated torque-wrench method in accordance with manufacturer’s published data.

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3. Confirm correct operation and sequencing of key-type mechanical interlock systems for multiple circuit breakers 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 barrier and shutter installation and operation.

5. Exercise all active components.

6. Inspect indicating devices for correct operation.

7. Perform an insulation-resistance test, phase to ground, on each bus section, with phases not under test grounded, in accordance with manufacturer’s published data.

8. Perform insulation-resistance tests on control wiring with respect to ground. Applied potential shall be 500 V DC for 300-volt rated cable and 1000 V DC for 600-volt 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 switchgear to insure correct bus phasing from each source.

1.5 SUBMITTALS

A. Submit in accordance with Paragraph, SUBMITTALS in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS, and the following requirements:

1. Shop Drawings:

a. Switchgear shop drawings shall be submitted simultaneously with or after the Overcurrent Protective Device Coordination Study.

b. Submit sufficient information to demonstrate compliance with drawings and specifications.

c. Prior to fabrication of switchgear, submit the following data for approval:

1) Complete electrical ratings.

2) Circuit breaker sizes.

3) Interrupting ratings.

4) Safety features.

5) Accessories and nameplate data.

6) Switchgear one line diagram, showing ampere rating, number of bars per phase and neutral in each bus run (horizontal and

26 23 00 - 3 vertical), bus spacing, equipment ground bus, and bus material.

7) Elementary and interconnection wiring diagrams.

8) Technical data for each component.

9) Dimensioned exterior views of the switchgear.

10) Dimensioned section views of the switchgear.

11) Floor plan of the switchgear.

12) Foundation plan for the switchgear.

13) Provisions and required locations for external conduit and wiring entrances.

14) Approximate design weights.

2. Manuals:

a. 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.

1) Schematic signal and control diagrams, with all terminals identified, matching terminal identification in the switchgear.

2) Include information for testing, repair, trouble shooting, assembly, disassembly, and factory recommended/required periodic maintenance procedures and frequency.

3) Provide a replacement and spare parts list. Include a list of tools and instruments for testing and maintenance purposes.

b. If changes have been made to the maintenance and operating manuals originally submitted, submit updated maintenance and operating manuals two weeks prior to the final inspection.

3. Certifications: Submit the following.

a. Certification by the manufacturer that switchgear conforms to the requirements of the drawings and specifications.

1.6 APPLICABLE PUBLICATIONS

A. Publications listed below (including amendments, addenda, revisions, supplements, and errata), form a part of this specification to the extent referenced. Publications are referenced in the text by basic designation only.

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B. Institute of Engineering and Electronic Engineers (IEEE):

C37.13-15...............Low-voltage AC Power Circuit Breakers Used in

Enclosures

C37.20.1-15.............Metal-Enclosed Low-Voltage Power Circuit

Breaker Switchgear

C57.13-16...............Instrument Transformers

C62.41.1-08.............Surge Environment in Low-voltage (1000V or less) AC Power Circuits

C62.45-08...............Surge Testing for Equipment connected to Low-

Voltage AC Power Circuits

C. International Code Council (ICC):

IBC-21..................International Building Code

D. National Electrical Manufacturers Association (NEMA):

C37.51-18...............Metal-Enclosed Low Voltage AC Power Circuit

Breaker Switchgear Assemblies — Conformance

Test Procedures

C37.51A-10..............Metal-Enclosed Low Voltage AC Power Circuit

Breaker Switchgear Assemblies — Conformance

Test Procedures Amendment 1 Short-Time

Withstand Current Tests

E. National Fire Protection Association (NFPA):

70-23...................National Electrical Code (NEC).

F. Underwriters Laboratories, Inc. (UL):

891-19 .................Switchboards

977-12..................Safety Fused Power-Circuit Devices

1053-15.................Ground Fault Sensing and Relaying Equipment

1558-16.................Metal-Enclosed Low-Voltage Power Circuit

Breaker Switchgear

PART 2 - PRODUCTS

2.1 GENERAL

A. Shall be in accordance with IEEE, NEMA, NFPA, UL, as shown on the drawings, and have the following features:

1. Switchgear shall be a complete, grounded, continuous-duty, integral assembly, metal clad, dead-front, dead-rear, self-supporting, indoor type switchgear assembly. Incorporate devices shown on the drawings and all related components required to fulfill operational and functional requirements.

2. Switchgear shall be Type 2 front, side, and rear accessible.

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3. Ratings shall not be less than shown on the drawings. Short circuit ratings shall not be less than 100kA.

4. Switchgear shall conform to the arrangements and details shown on the drawings.

5. Key-type mechanical interlocks for multiple circuit breakers shall be provided as shown on the drawings.

6. Switchgear shall be assembled, connected, and wired at the factory so that only external circuit connections are required at the construction site. Split the structure only as required for shipping and installation. Packaging shall provide adequate protection against rough handling during shipment.

2.2 HOUSING

A. Shall have the following features:

1. Frames and enclosures:

a. The assembly shall be braced with reinforcing gussets using bolted connections to assure rectangular rigidity.

b. The enclosure shall be steel, leveled, and not less than the gauge required by applicable publications.

c. Die-pierce the holes for connecting adjacent structures to insure proper alignment, and to allow for future additions.

d. All bolts, nuts, and washers shall be cadmium-plated steel.

2. Circuit breaker compartments:

a. An individual compartment shall be supplied for each circuit breaker and each future circuit breaker as shown on the drawings.

Compartments shall be provided with isolated wireways for control wiring between devices.

1) Separate each compartment so that the circuit breaker, buses, and cable terminations are in separate compartments with steel partitions or barriers of approved and properly installed insulation.

2) Each compartment furnished with a circuit breaker (active or spare) shall be fully equipped as noted on drawings and specified below.

3) Each compartment noted as space for future circuit breaker, as shown on drawings, shall be fully equipped for positioning and connecting the breaker. Provide all equipment required to implement the future breaker installation.

3. Auxiliary compartments:

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a. Compartments shall be provided for auxiliaries, metering, and transition or termination sections as required by the manufacturer, and as shown on drawings. Compartments shall be provided with isolated wireways for control wiring between devices.

4. Compartment doors:

a. The doors shall permit convenient removal and interchanging of circuit breakers between compartments. The doors shall be capable of a swing approaching 180 degrees.

b. Concealed or semi-concealed hinges shall be provided to attach the doors. Weld the hinges to the equipment structure and to the compartment doors.

B. Finish:

1. All metal surfaces shall be thoroughly cleaned, phosphatized and factory primed prior to applying baked enamel or lacquer finish.

2. Provide a light gray finish for indoor switchgear.

2.3 BUSES

A. Bus Bars and Interconnections:

1. Provide copper phase and neutral buses, fully rated for the amperage as shown on the drawings for the entire length of the switchgear.

Bus laminations shall have a minimum of 6 mm (1/4 inch) spacing.

2. Mount the buses on appropriately spaced insulators and brace to withstand the available short circuit currents.

3. The bus and bus compartment shall be designed so that the acceptable

NEMA standard temperature rises are not exceeded.

4. Install a copper ground bus the full length of the switchgear assembly.

5. Main Bonding Jumper: An un-insulated copper bus, size as shown on drawings, shall interconnect the neutral and ground buses, when the switchgear is used to establish the system common ground point.

6. All bolts, nuts, and washers shall be cadmium-plated steel. Bolts shall be torqued to the values recommended by the manufacturer.

7. Make provisions for future bus extensions by means of bolt holes or other approved method.

2.4 LOW-VOLTAGE POWER CIRCUIT BREAKERS

A. General: Circuit breakers shall be dead front, drawout, stored energy type with solid state trip devices. Arcing contacts shall be renewable.

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B. Rating: Circuit breakers shall be 3 pole, 600 volts AC and below, 60 cycle with frame size, trip rating and functions, and system voltage as shown on drawings. Breakers shall have 30 cycle short time current ratings.

C. Draw-out Mounting: Provide a racking mechanism to position and hold the breaker in the connected, test, or disconnected position. Provide an interlock to prevent movement of the breaker into or out of the connected position unless the breaker is tripped open.

D. Trip Devices: Breakers shall be electrically and mechanically trip free and shall have trip devices in each pole. Unless otherwise indicated on drawings, each breaker shall have overcurrent and short-circuit , and integral ground fault trip devices. Trip devices shall be of the solid state type with adjustable pick-up settings, with both long time and short time elements, and integral trip unit testing provisions.

Devices shall have time-delay band adjustment. Long-time delay element shall have inverse time characteristics. Main circuit breakers shall have instantaneous trip function that can be turned off.

E. Position Indicator: Provide a mechanical indicator visible from the front of the unit to indicate whether the breaker is open or closed.

F. Trip Button: Equip each breaker with a mechanical trip button accessible from the front of the door.

G. Padlocking: Provisions shall be included for padlocking the breaker in the open position.

H. Operation: Unless otherwise indicated herein or on the drawings, breakers 1600 ampere frame size and less shall be manually operated.

Breakers larger than 1600 ampere frame size shall be electrically operated.

2.7 SURGE PROTECTIVE DEVICE

A. Not Used.

2.8 METERING

A. Refer to drawings for meter locations.

B. As necessary, provide compartment with a front hinged door to provide safe isolated access to meters and all associated terminal and fuse blocks for maintenance, calibration, or testing.

C. Provide current transformers for each meter. Current transformers shall be wired to shorting-type terminal blocks.

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D. Provide voltage transformers including primary fuses and secondary protective devices for metering as shown on the drawings.

2.9 OTHER EQUIPMENT

A. Furnish tools and accessories required for circuit breaker and switchgear test, inspection, maintenance, and proper operation.

C. Circuit breaker removal equipment: Furnish a permanent circuit breaker removal device mounted on top of enclosure for installation and removal of circuit breakers.

2.10 CONTROL WIRING

A. Switchgear control wires shall not be less than No. 14 AWG copper 600 V rated. Install wiring complete at the factory, adequately bundled and protected. Provide separate control circuit fuses in each breaker compartment and locate for ease of access and maintenance.

2.11 NAMEPLATES AND MIMIC BUS

A. Nameplates: Provide laminated black phenolic resin with white core with

12 mm (1/2 inch) engraved lettered nameplates 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 adhesive is not acceptable.

B. Mimic Bus: Provide an approved mimic bus on front of each switchgear assembly. Color shall be black, either factory-painted plastic or metal strips. Plastic tape shall not be used. Use symbols similar to one line diagram shown on drawings. Plastic or metal strips shall be mounted with plated screws.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Not Used.

3.2 ACCEPTANCE CHECKS AND TESTS

A. Perform in accordance with the manufacturer's recommendations.

In addition, include the following:

1. After assembly, the complete switchgear shall be tested to ensure the accuracy of the wiring and functioning of all equipment. The main bus system shall be given a dielectric test of 2200 volts for one minute between live parts and ground and between opposite polarities.

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2. The wiring and controls circuits shall be given a dielectric test of

1500 volts for one minute, or 1800 volts for one second, between live parts and ground, in accordance with ANSI C37.20.1.

3. A certified test report of all standard production tests shall be shipped with each assembly.

2. Electrical tests:

a. Perform insulation-resistance tests on each bus section.

b. Perform insulation-resistance test on control wiring; do not perform this test on wiring connected to solid-state components.

c. Perform phasing check on double-ended switchgear to ensure correct bus phasing from each source.

3.3 FOLLOW-UP VERIFICATION

A. Not Used

3.4 TEMPORARY HEATING

A. Not Used.

3.5 WARNING SIGN

A. Not Used.

3.6 ONE LINE DIAGRAM AND SEQUENCE OF OPERATION

A. Not Used.

3.7 AS-LEFT TRIP UNIT SETTINGS

A. The trip unit settings shall be set in the field by an authorized representative of the switchgear manufacturer per the approved

Overcurrent Protective Device Coordination Study in accordance with

Section 26 05 73, OVERCURRENT PROTECTIVE DEVICE COORDINATION STUDY.

B. Post a durable copy of the "as-left" trip unit settings in a convenient location in the switchgear room. Deliver four additional copies of the settings to the Resident Engineer prior to the activation of the switchgear.

3.8 INSTRUCTION

A. Furnish the services of a factory-trained technician for two, 4-hour training periods for instructing personnel in the maintenance and operation of the switchgear, on the dates requested by the Resident

Engineer.

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