262413 Distribution Switchboard.pdf

Louisville KY - Robley Rex VAMC – Upgrade 480V Electrical System

Project #: 603-20-505 01-01-18

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SECTION 26 24 13

DISTRIBUTION SWITCHBOARDS

PART 1 - GENERAL

1.1 DESCRIPTION

A. This section specifies the furnishing, installation, connection, and testing of the low-voltage circuit-breaker distribution switchboards, indicated as switchboard(s) 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 19, LOW-VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES:

Low-voltage conductors.

C. 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.

D. Section 26 05 33, RACEWAY AND BOXES FOR ELECTRICAL SYSTEMS: Conduit.

E. 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 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. Switchboard 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 switchboards, submit the following data for approval:

1) Complete electrical ratings.

2) Circuit breaker sizes.

3) Interrupting ratings.

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4) Safety features.

5) Accessories and nameplate data.

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

10) Dimensioned section views of the switchboard.

11) Floor plan of the switchboard.

12) Foundation plan for the switchboard.

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 switchboard.

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: Two weeks prior to final inspection, submit the following.

a. Certification by the manufacturer that the switchboards conform to the requirements of the drawings and specifications.

b. Certification by the Contractor that the switchboards have been properly installed, adjusted, and tested.

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1.5 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.

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

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

Enclosures

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

C62.41.1-02.............Surge Environment in Low-voltage (1000V and less) AC Power Circuits

C62.45-02...............Surge Testing for Equipment connected to Low-

Voltage AC Power Circuits

C. International Code Council (ICC):

IBC-15..................International Building Code

D. National Electrical Manufacturer's Association (NEMA):

PB 2-11.................Deadfront Distribution Switchboards

PB 2.1-13...............Proper Handling, Installation, Operation, and

Maintenance of Deadfront Distribution

Switchboards Rated 600 Volts or Less

E. National Fire Protection Association (NFPA):

70-17...................National Electrical Code (NEC)

F. Underwriters Laboratories, Inc. (UL):

67-09...................Panelboards

489-16..................Molded-Case Circuit Breakers, Molded-Case

Switches, and Circuit-Breaker Enclosures

891-05..................Switchboards

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

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2. Ratings shall not be less than shown on the drawings. Short circuit ratings shall not be less than the available fault current shown in the Overcurrent Protective Device Coordination Study.

3. Switchboard shall conform to the arrangements and details shown on the drawings.

4. All non-current-carrying parts shall be grounded per Section 26 05

26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS for additional requirements.

5. Series rated switchboards are not allowed.

2.2 BASIC ARRANGEMENT

A. Type 1: Switchboard 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 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.

2.3 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 zinc-plated steel.

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 switchboard.

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2.4 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 switchboard.

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 switchboard assembly.

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

6. All bolts, nuts, and washers shall be zinc-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.

2.5 FEEDER CIRCUIT BREAKERS

A. Provide molded case circuit breakers as shown on the drawings.

B. Adjustable Trip Molded Case Circuit Breakers:

1. Provide molded case, solid state adjustable trip type circuit breakers.

2. Trip units shall have field adjustable tripping characteristics as follows:

a. Long time pickup.

b. Long time delay.

c. Short time pickup.

d. Short time delay.

e. Instantaneous.

2.6 OTHER EQUIPMENT

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

2.7 NAMEPLATES

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

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System, provide laminated red 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.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Install switchboards in accordance with the NEC, as shown on the drawings, and as recommended by the manufacturer.

B. Anchor switchboards with rustproof bolts, nuts, and washers not less than 13 mm (1/2 inch) diameter, in accordance with manufacturer’s instructions, and as shown on drawings.

C. Interior Location. Mount switchboard on concrete slab. Unless otherwise indicated, the slab shall be at least 100 mm (4 inches) thick. The top of the concrete slab shall be approximately 100 mm (4 inches) above finished floor. Edges above floor shall have 12.5 mm (1/2 inch) chamfer. The slab shall be of adequate size to project at least

200 mm (8 inches) beyond the equipment. Provide conduit turnups and cable entrance space required by the equipment to be mounted. Seal voids around conduit openings in slab with water- and oil-resistant caulking or sealant. Cut off and bush conduits 75 mm (3 inches) above slab surface. Concrete work shall be as specified in Section 03 30 00, CAST-IN-PLACE CONCRETE.

3.2 ACCEPTANCE CHECKS AND TESTS

A. Perform in accordance with the manufacturer's recommendations. In addition, include the following:

1. Visual Inspection and Tests:

a. Compare equipment nameplate data with specifications and approved shop drawings.

b. Inspect physical, electrical, and mechanical condition.

c. Verify appropriate anchorage, required area clearances, and correct alignment.

d. Verify that circuit breaker sizes and types correspond to approved shop drawings.

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e. Verifying tightness of accessible bolted electrical connections by calibrated torque-wrench method, or performing thermographic survey after energization.

f. Vacuum-clean switchboard enclosure interior. Clean switchboard enclosure exterior.

g. Inspect insulators for evidence of physical damage or contaminated surfaces.

h. Verify correct shutter installation and operation.

i. Exercise all active components.

j. Verify the correct operation of all sensing devices, alarms, and indicating devices.

k. Verify that vents are clear.

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 switchboards to ensure correct bus phasing from each source.

3.3 FOLLOW-UP VERIFICATION

A. Upon completion of acceptance checks, settings, and tests, the

Contractor shall show by demonstration in service that the switchboard is in good operating condition and properly performing the intended function.

3.6 AS-LEFT TRIP UNIT SETTINGS

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

Electrical System Protective Device 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 switchboard room. Deliver four additional copies of the settings to the COR. Furnish this information prior to the activation of the switchboard.

3.7 INSTRUCTION

A. Furnish the services of a factory-trained technician for one, 4-hour training period for instructing personnel in the maintenance and operation of the switchboards, on the dates requested by the COR.

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