This equipment specification guide provides information for describing a typical metal enclosed low voltage power circuit breaker switchgear assembly. Items or features that are non-standard but required for a specific application are preceded by (option). Items preceded or followed by a blank (__) require that additional data be provided in order to complete the specification.
General
The equipment to be supplied shall be metal enclosed low-voltage power circuit breaker switchgear with drawout circuit breaker elements. All power circuit breakers and assemblies shall be produced by a single manufacturer and shall be designed, tested and manufac- tured in accordance with the standards referenced in this specification.
Codes and Standards
The switchgear assemblies and power cir- cuit breakers shall comply with the codes and standards as indicated. Copies of cer- tified design tests shall be furnished if requested to confirm compliance.
JANSI / IEEE C37.13 — Low- Voltage AC Power Circuit Breakers Used in Enclosures
JANSI C37.16 — Low-Voltage Power Circuit Breakers and AC Power Circuit Protectors — Preferred Ratings, Related Requirements, and Application Recommendations
JANSI C37.17 — Trip Devices for AC and General Purpose DC Low- Voltage Power Circuit Breakers
JANSI / IEEE C37.20.1 — Metal- Enclosed Low-Voltage Power Circuit-Breaker Switchgear
JANSI / IEEE C37.27 — Application Guide for Low-Voltage AC Nonintegrally Fused Power Circuit Breakers (Using Separately Mounted Current Limiting Fuses)
JANSI C37.50 — Standard Test Procedures for Low-Voltage AC Power Circuit Breakers Used in Enclosures.
JANSI C37.51 — Standard Conformance Test Procedures for Metal Enclosed Low-Voltage AC Power Circuit-Breaker Switchgear Assemblies
JANSI / NEMA 250 — Enclosures for Electrical Equipment (1000 Volts Maximum)
JNEMA SG 3 — Low-Voltage Power Circuit Breakers
JNEMA SG 5 — Power Switchgear Assemblies
J(option) NEMA 210 — Secondary Unit Substations
JUL 1066 — Low-Voltage AC and DC Power Circuit Breakers Used in Enclosures
J(Option) UL 1558 — Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear
Assembly
The switchgear assembly shall be Siemens Type R and is to be located indoors, with a NEMA 1 enclosure, (option) outdoor, NEMA 3R per specifications below and constructed of multiple, metal-enclosed, ventilated sections. The front of each verti- cal section is to contain three or four com- partments with 14 gauge steel side sheets and compartment barriers of 11 gauge steel. A double thickness of 14 gauge steel is to be provided between vertical sec- tions. The side sheets shall be full height and depth to provide a full metal barrier separating the rear cable compartments between sections. End sections shall include provisions for main bus extension and installation of future vertical sections. The design shall incorporate preformed steel channels, angles, and side sheets bolted together and reinforced to form a rigid, self-supporting, compact assembly.
Horizontal barriers are to be provided to form individual circuit breaker or metering com- partments. Circuit breaker compartments are to be barriered from the bus compart- ment through a primary disconnect assem- bly. Each circuit breaker or metering com- partment shall be provided with a hinged front door secured with rotary latches requir- ing no tools to operate.
Circuit breaker compartments shall include stationary primary contact disconnects. The primary disconnects shall be copper, silver-plated at connection points and shall be of one piece construction. The upper set of disconnects shall bolt directly to the main bus and, for feeder circuit breakers, the lower set shall extend to the rear cable area and shall be insulated where they pass through the main bus compartment. Primary disconnects shall be sized for the maximum continuous current of the circuit breaker which will be located in the com- partment. Interlocks shall be provided which will prevent a circuit breaker ele- ment of the incorrect frame size or inter- rupting rating from being inserted into the compartment. A stationary circuit breaker frame grounding contact shall be provided which shall be visible with the circuit breaker installed in any position.
Secondary control contacts, when required, shall be located in the circuit breaker compartment and shall be of the sliding contact, silver-plated copper design. Barriers shall be provided between terminal points. The secondary control contacts shall engage the drawout circuit breaker element in the connected and test positions.
Control circuit fuses for electrically oper- ated circuit breakers shall be located on the side of the circuit breaker compart- ment and shall be contained in a dead- front, pull-out fuse block with a clear cover. Withdrawing the cover from the fuse block shall automatically remove the control circuit fuses and hold them cap- tive. The fuse block cover shall include provisions for being installed in the reverse position in order to maintain the open control circuit for testing or mainte- nance purposes while continuing to hold the fuses captive.
All control wiring within the assembly shall be continuous and shall terminate on each end at a suitable terminal block. Control wiring shall be 14 gauge, strand- ed, type SIS, and shall be labeled at each end with sleeve type wire markers. Wire markers shall be machine imprinted with the wire name as indicated on the wiring diagrams. Wrap on wire markers will not be accepted. Terminals shall be insulated locking fork or ring tongue type except where connecting to components that do not accept these terminations. Control wiring for external connections shall be terminated in the rear cable area for ease of access. (Option) Metal covers shall be provided over control wiring troughs where they pass through the power cable termination area. (Option) Metal covers shall be provided over terminal blocks located in the power cable termi- nation area.
Bus
Main bus shall be three-phase, ___ wire
___ ampere copper with silver-plated connection joints (option) aluminum with welded connection points (option) copper with tin-plated connection points. (Option) Neutral bus rating shall be ___% of the main bus current rating and shall be located centrally in the structure for ease of terminating cables whether entering from above or below. 600 volt clearances shall be maintained in all hori- zontal and vertical buses such that insula- tion is not required. The main horizontal bus shall be run in a vertical, edge-to- edge arrangement for high short circuit strength. Access to the rear cable termi- nation area shall be possible without
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480V Metal Switchgear- Enclosed
