SECTION 16426

DISTRIBUTION SWITCHBOARDS

PART 1	GENERAL

SECTION INCLUDES

Main switchboard.

Distribution switchboard.

RELATED SECTIONS

Section 03300 - Cast-in-Place Concrete: Concrete pads.

Section 09900 - Painting.

Section 16421 - Utility Service Entrance: Utility metering equipment.

Section 16465 - Feeder and Plug-In Busway.

REFERENCES

ANSI/NFPA 70 - National Electrical Code.

ANSI/IEEE C12.1 - Code for Electricity Metering.

ANSI C39.1 - Electrical Analog Indicating Instruments.

ANSI C57.13 - Instrument Transformers.

NEMA AB 1 - Molded Case Circuit Breakers and Molded Case Switches.

NEMA KS 1 - Enclosed Switches.

NEMA PB 2 - Deadfront Distribution Switchboards.

NEMA PB 2.1 - Proper Handling, Installation, Operation and Maintenance of Deadfront Switchboards Rated 600 Volts or Less.

SUBMITTALS

Submit under provisions of Section [01300] [_____].

Shop Drawings: Indicate front and side views of enclosures with overall dimensions shown; conduit entrance locations and requirements; nameplate legends; size and number of bus bars per phase, [neutral,] and ground; and switchboard instrument details.

Product Data: Provide electrical characteristics including voltage, frame size and trip ratings, fault current withstand ratings, and time-current curves of all equipment and components.

Test Reports: Indicate results of factory production tests.

Manufacturer's Instructions:	Indicate application conditions and limitations of use stipulated by Product testing agency specified under Regulatory Requirements. Include instructions for storage, handling, protection, examination, preparation, installation, and starting of Product.

OPERATION AND MAINTENANCE DATA

Submit under provisions of Section [01700] [_____].

Maintenance Data: Include spare parts data listing; source and current prices of replacement parts and supplies; and recommended maintenance procedures and intervals.

QUALIFICATIONS

Manufacturer: Company specializing in manufacturing Products specified in this Section with minimum [three] [_____] years [documented] experience.

REGULATORY REQUIREMENTS

Conform to requirements of ANSI/NFPA 70.

Furnish products listed and classified by [Underwriters Laboratories, Inc.] [testing firm acceptable to authority having jurisdiction] as suitable for purpose specified and shown.

PRE-INSTALLATION CONFERENCE

Convene [one] [_____] week prior to commencing work of this Section, under provisions of Section [01039] [_____].

DELIVERY, STORAGE, AND HANDLING

Deliver, store, protect, and handle products to site under provisions of Section [01600] [______].

Deliver in [48] [___] inch ([1.2] [___] m) maximum width shipping splits, individually wrapped for protection and mounted on shipping skids.

Accept switchboards on site. Inspect for damage.

Store in a clean, dry space.	Maintain factory wrapping or provide an additional heavy canvas or heavy plastic cover to protect units from dirt, water, construction debris,

and traffic.

Handle in accordance with NEMA PB 2.1 and manufacturer's written instructions. Lift only with lugs provided for the purpose. Handle carefully to avoid damage to switchboard internal components, enclosure, and finish.

ENVIRONMENTAL REQUIREMENTS

Conform to NEMA PB 2 service conditions during and after installation of switchboards.

FIELD MEASUREMENTS

Verify that field measurements are as [indicated [on shop drawings]] [instructed by manufacturer].

MAINTENANCE MATERIALS

Provide maintenance materials under provisions of Section [01700] [_____].

Provide [two] [____] of each key.

Provide [two] [____] fuse pullers.

EXTRA MATERIALS

Furnish under provisions of Section [01700] [_____].

Provide [three] [____] of each size and type of fuse installed.

PART 2	PRODUCTS

MANUFACTURERS

[_________________________________ Model [_________].

[________________________________] Model [_________].

[________________________________] Model [_________].

Substitutions: Under provisions of Section [01600] [_____].

SWITCHBOARD

Description:	NEMA PB 2 with electrical ratings and configurations as indicated.

Main Section Devices: [Panel mounted.] [Individually mounted.] [Individually mounted and compartmented.]

Distribution Section Devices: [Panel mounted.] [Individually mounted.] [Individually mounted and compartmented.]

Auxiliary Section Devices: [Individually mounted.] [Individually mounted and compartmented.]

Bus Material: [Copper] [Copper with tin plating] [Aluminum with tin plating], standard size.

Bus Connections:	[Bolted] [Welded], accessible from [front] [rear only] for maintenance.

Fully insulate [load side] bus bars [in rear accessible compartments]. [Do not reduce spacing of insulated bus.] Use [______________________________] for insulating material.

Ground Bus: Extend length of switchboard.

**** OR ****

Insulated Ground Bus: Extend length of switchboard.

Fusible Switch Assemblies: NEMA KS 1, load interrupter enclosed knife switch with externally operable handle. Provide interlock to prevent opening front cover with switch in ON position. Handle lockable in OFF position. Fuse clips: Designed to accommodate Class [R] [J] fuses, type as specified.

Fusible Switch Assemblies, 800 Amperes and Larger: Bolted pressure contact switches. Fuse clips: Designed to accomodate Class L fuses.

Molded Case Circuit Breakers: NEMA AB 1, integral thermal and instantaneous magnetic trip in each pole. [Provide circuit breakers UL listed as Type HACR for air conditioning equipment branch circuits.]

Molded Case Circuit Breakers with Current Limiters: NEMA AB 1, molded case circuit breakers with replaceable current limiting elements, in addition to integral thermal and instantaneous magnetic trip in each pole.

Current Limiting Molded Case Circuit Breakers: NEMA AB 1, molded case circuit breakers with integral thermal and instantaneous magnetic trip in each pole, coordinated with automatically reseting current limiting elements in each pole. Interrupting rating 100,000 rms amperes symetrical let-through current and energy level less than permitted for same size Class RK-5 fuse.

Solid-state Molded Case Circuit Breakers: NEMA AB 1, provide with electronic sensing, timing and tripping circuits for adjustable current settings; [ground fault trip]; instantaneous trip; and adjustable short time trip. Provide [stationary mounting.] [drawout construction.] [[Provide ground fault sensing integral with circuit breaker.] [Provide zero sequence type ground fault sensor.]]

Line and Load Terminations: Accessible from the [front only] [rear] of the switchboard, suitable for the conductor materials and sizes indicated.

Ground Fault Sensor:	[Zero sequence] [Ground return] type.

Ground Fault Relay: Adjustable ground fault sensitivity from 200 to 1200 amperes, time delay [______] [adjustable from 0 to 15] seconds. Provide monitor panel with lamp to indicate relay operation, TEST and RESET control switches.

Provide metering transformer compartment for Utility Company's use. Provide compartment size, bus spacing and drilling, door, and locking and sealing requirements in accordance with Section 16421.

Pull Section: [Size as shown on Drawings.] [[18] [_____ ] inch ([450] [______ ] mm.) width, depth and height to match switchboard.] Arrange [as shown on Drawings.] [with pull section on [left] [right] side of switchboard as viewed from the front.]

Future Provisions: Fully equip spaces for future devices with bussing and bus connections, suitably insulated and braced for short circuit currents. Provide continuous current rating as indicated.

Pull Box: Removable top and sides, same construction as switchboard, [size as shown on Drawings.] [[______ ] inch ([______ ] mm) height over top switchboard.] [Set front back sufficient distance to accommodate circuit breaker lifting devices.] Provide insulating, fire-resistive bottom with separate openings for each circuit to pass into switchboard.

Enclosure:	Type [1 - General Purpose.] [2 - Raintight.]

Align sections at [front and rear.] [rear only.] [front only.]

Switchboard Height: [_____] inches ( [____] M), excluding floor sills, lifting members and pull boxes.

Finish: Manufacturer's standard light gray enamel over external surfaces. Coat internal surfaces with minimum one coat corrosion-resisting paint, or plate with cadmium or zinc.

Mimic Bus: Show bussing, connections and devices in single line form on the front panels of the switchboard using [blue] [black] [___________ ] color [factory painting] [plastic strips] [light metal strips] [_________________ ] [, fastened flat against the panel face with [screws or rivets.] [adhesive.]]

2.03	FUSES

Manufacturers:

[________________________________] Model [_________].

[________________________________] Model [_________].

[________________________________] Model [_________].

Substitutions: Under provisions of Section [01600] [_____].

Fuses 600 Amperes and Less: [Dual element,] current limiting, [time delay,] one-time fuse, [250] [600] volt, UL Class [RK 1.] [RK 5.] [J.] [as indicated].]

Fuses 601 Amperes and Larger: Current limiting, [time delay] [fast-acting] one time fuse, 600 volt, UL Class L.

Interrupting Rating: 200,000 rms amperes.

AMMETERS AND VOLTMETERS

Manufacturers:

1.[________________________________] Model [_________].

2.[________________________________] Model [_________].

3.[________________________________] Model [_________].

4.Substitutions: Under provisions of Section [01600]

[_____].

Ammeters: ANSI C39.1; direct-reading, full range, indicating ammeter with 4.5 inch (115 mm) square recessed case and 250 degree scale, white dial with black figures and pointer, 5 ampere, 60 Hertz movement, 1 percent accuracy.

Voltmeters: ANSI C39.1; direct-reading, full range, indicating voltmeter with 4.5 inch (115 mm) square recessed case and 250 degree scale, white dial with black figures and pointer, 120 volt, 60 Hertz movement, 1 percent accuracy.

METER TRANSFER SWITCHES

Manufacturers:

[________________________________] Model [_________].

[________________________________] Model [_________].

[________________________________] Model [_________].

Substitutions: Under provisions of Section [01600] [_____].

Ammeter Transfer Switch:	Rotary multistage snap-action type with 600 volt AC-DC silver plated contacts, engraved escutcheon plate, [pistol-grip] [oval type] handle, and four positions including OFF.

Voltmeter Transfer Switch: Rotary multistage snap-action type with 600 volt AC-DC silver plated contacts, engraved escutcheon plate, [pistol-grip] [oval type] handle, and [four] [seven] positions including OFF.

POWER METERS

Manufacturers:

[________________________________] Model [_________].

[________________________________] Model [_________].

[________________________________] Model [_________].

Substitutions: Under provisions of Section [01600] [_____].

Watt-hour Meters and Wattmeters:	ANSI/IEEE C12.1; three phase induction type with two stators, each with current and potential coil, rated 5 amperes and 120 volts at 60 Hertz. Meter suitable for connection to 3- and 4-wire circuits. Include potential indicating lamps; adjustments for light and full load, phase balance, and power factor; four-dial clock register; [integral demand indicator] [contact devices to operate remote impulse-totalizing demand meter]; ratchets to prevent reverse rotation; removable meter with draw-out test plug; semi-flush mounted case with matching cover.

Impulse-Totalizing Demand Meter:	ANSI/IEE C12.1; suitable for use with switchboard watt-hour meter, including two circuit totalizing relay; cyclometer; [four dial totalizing kilowatt-hour register;] positive chart drive mechanism; capillary pen holding minimum one-month ink supply; and a roll chart with minumum 31-day capacity. Indicate and record [five minute] [fifteen minute] [30 minute] [_______ ] integrated demand of the totalized system.

Provide meters with appropriate multiplier tags.

METERING TRANSFORMERS

Manufacturers:

[________________________________] Model [_________].

[________________________________] Model [_________].

[________________________________] Model [_________].

Substitutions: Under provisions of Section [01600]

[_____].

Current Transformers: ANSI C57.13; 5 ampere secondary, [wound] [bushing] [bar or window] type, with [single] [double] secondary winding and secondary shorting device, primary/secondary ratio as [required] [shown on Drawings], burden and accuracy consistent with connected metering and relay devices, 60 Hertz.

Potential Transformers: ANSI C57.13; 120 volt [single] [tapped] [double] secondary, disconnecting type with integral fuse mountings, primary/secondary ratio as [required] [indicated], burden and accuracy consistent with connected metering and relay devices, 60 Hertz.

ACCESSORIES

Circuit Breaker Lifting Device: [Portable, floor supported, elevating carriage with a roller base, for movement of circuit breakers in and out of switchboard structure.] [Carriage and track on top of each switchboard with lifting device to serve draw-out circuit breakers in switchboard.]

Provide thermostatically-controlled electric heaters in each section, sized to prevent condensation under expected weather conditions at Project site. Provide terminals for separate connection of heater power circuit. Voltage Rating: [120] [____] volts.

PART 3	EXECUTION

EXAMINATION

Verify conditions under provisions of Section [01039] [_____].

Verify that surface is suitable for switchboard installation.

PREPARATION

Provide concrete housekeeping pad under the provisions of Section [03300.] [_____.]

INSTALLATION

Install switchboard in locations shown on Drawings, in accordance with manufacturer's written instructions and NEMA PB 2.1.

Tighten accessible bus connections and mechanical fasteners after placing switchboard.

Install fuses in each switch.

FIELD QUALITY CONTROL

Field [inspection and] testing will be performed under provisions of Section [01400] [_____].

Inspect completed installation for physical damage, proper alignment, anchorage, and grounding.

Measure insulation resistance of each bus section phase to phase and phase to ground for one minute each, at test voltage of 1000 volts; minimum acceptable value for insulation resistance is 2 megohms.

Check tightness of accessible bolted bus joints using calibrated torque wrench.

Physically test key interlock systems to insure proper function.

ADJUSTING

Adjust all operating mechanisms for free mechanical movement.

Tighten bolted bus connections in accordance with manufacturer's instructions.

Adjust circuit breaker trip and time delay settings to values [indicated.] [as instructed by the Architect/Engineer.]

CLEANING

Touch up scratched or marred surfaces to match original finish.

END OF SECTION