Circuit Breakers, Solid State Trip Units, Outdoor

480V Metal-Enclosed Switchgear

Guide Form Specifications

Specifications

480V Enclosed-MetalSwitchgear

reaching over the main and vertical bus. Bus bracing shall be equal to the short circuit interrupting rating of the lowest rated non-fused circuit breaker applied in the assembly. A 0.25 in. (6 mm) by 2.00 in. (51 mm) copper ground bus will be provid- ed. Barriers shall be provided which isolate the rear cable termination compartment from the adjacent vertical section. (Option) Barriers shall be provided to isolate the rear cable area from the main bus area. (Option) Barriers shall be provided to sepa- rate the incoming line connections from the main horizontal and vertical bus.

Circuit Breakers

Circuit breakers shall be Siemens Type RL and shall be either electrically or manually operated as indicated on the data sheets (or drawings). Minimum interrupting rat- ings will be as defined on the data sheets (or drawings) and shall meet or exceed the interrupting ratings as defined by ANSI standards. (Option) Fused circuit breakers are to be the integrally fused type through the 2000 ampere frame size. 3200 and 4000 ampere frame sizes are to be sup- plied with separate drawout fuse carriages which are mounted in the same vertical section as the circuit breaker element and are to be key interlocked with the circuit breaker element such that the fuse carriage cannot be withdrawn unless the circuit breaker is locked in the open position. All fused circuit breakers are to be equipped with blown fuse lockout devices to prevent single phasing. The application of fused circuit breakers shall not reduce the amount of rear cable termination space which would have been provided with non- fused circuit breakers.

Circuit breakers are to be 600 volt class with nominal ratings as dictated by the system voltage. Circuit breakers shall be three-pole, single-throw, operated by a stored energy mechanism, with arc quenchers, main and arcing contact struc- ture, a three-phase solid state trip overcur- rent trip unit, trip actuator, three single ratio tripping sensors, and primary disconnect- ing devices. In addition, the circuit breaker element shall have connected, test, and disconnected position indicators, spring charged/discharged indicators, and circuit breaker open or closed indicators all of which shall be visible to the operator with the compartment door closed. It shall be possible to rack the circuit breaker element from the disconnect to the connected posi- tion with the compartment door closed. Interlocks will be provided that prevent racking a circuit breaker unless the circuit breaker is open and that prevent closing a circuit breaker unless it is in the connected or test position.

Solid State Trip Units

Solid state trip units shall be Siemens

JStatic Trip III (basic device)

J(Option) Static Trip IIIC (adds communications capability)

J(Option) Static Trip IIICP (adds communications and power metering)

J(Option) Static Trip IIICPX (adds communications, power metering, and relaying functions)

Trip units shall be interchangeable so that any trip unit can be used with any frame size circuit breaker. The basic trip unit shall be a self powered, micro-processor based device that measures true RMS currents. Long time, short circuit or ground fault trip indication shall be maintained for a mini- mum of 48 hours without the need for a separate battery or relay. Peak sensing devices will not be accepted. All adjust- ment setting switches shall be digitally encoded type with gold contacts. (Note: Refer to catalog section SGBR-3169B for specifications on the Siemens Static Trip III trip unit family and all associated options).

Instrumentation and Metering

A wide variety of user defined metering and instrumentation options are available. They include Siemens 4720, 4700 & 4300 power meters, Siemens Static Trip III trip units, and traditional analog devices. For more detailed specification information on Siemens devices refer to bulletins SGFL 3181B, 3161A, and 3151B for 4720, 4700, and 4300 power meters, respectively; and SGBR-3169B Static Trip III Micro-processor Based Tripping System. If one of the options selected requires separate voltage and current transformers, such as the Siemens 4700 power meter, the following may be used to define these devices.

Current transformers shall have standard accuracy class ratings as defined by ANSI C37.20.1 and shall be mounted directly on the stationary primary disconnects in the circuit breaker compartment. Voltage trans- formers shall have a minimum 150VA thermal rating and shall be located in a metal enclosed metering compartment and shall be protected on the primary side with current limiting fuses.

Outdoor

(Option) Outdoor, NEMA 3R, walk-in, weatherproof construction is to be provided. The complete assembly is to rest on a formed steel base provided under each vertical section and running perpendicular to the depth of the switchgear. The under- side of the enclosure and base structure is to be undercoated with coal tar emulsion material.

Front and rear doors are to be gasketed and hinged. Front doors, located at each end, are to include panic release door hard- ware, three point latches, and provision for padlocking. Rear doors shall be bolted. All exterior hardware shall be stainless steel.

An indoor access aisle approximately 42 in. (1067 mm) deep and accessible from either door is to be provided at the front of the switchgear line-up for inspection and testing of the circuit breakers and associat- ed equipment. A hand-operated traveling hoist, mounted above the switchgear is to be provided for changeout of circuit break- ers. The aisle is to have an extension on each end to accommodate end unit doors that have instrumentation and metering, and to provide additional space for circuit breaker handling.

The switchgear is to include space heaters to prevent condensation of moisture. The aisle shall be provided with incandescent lights, convenience receptacle, and an ON

/OFF switch at each end to control the lights.

Finish

During construction, the structural steel parts, panels, and compartments shall be prepared for painting by a five-stage wash system consisting of an alkaline cleaner, fresh water rinse, iron phosphate treat- ment, fresh water rinse, and non-chromate sealer. After cleaning and stabilization, the steel parts shall be coated with a ther- mosetting polyester powder applied with electrostatic equipment at a nominal 2 mils dry film thickness and then cured at 425 degrees Fahrenheit for 20 minutes. Paint color shall be ANSI 61 light gray. The paint finish shall have a pencil hardness of 2H, a gloss as defined by ANSI D523-78 of 45- 55%, a salt spray rating per ASTM B-117- 73 of 600 hours, and shall be outdoor rated per UL1332.

Accessories

The following accessories are to be provided:

Jcrank for racking circuit breakers

Jlifting yoke for circuit breakers

Jcontainer of touch-up paint

J(optional) portable test set, type PTS4

Joverhead hoist for indoor switchgear

J(optional) test cabinet

Testing

Production tests in accordance with ANSI C37.20.1, ANSI C37.50, ANSI C37.51 and NEMA SG 5 shall be performed on the completed assembly. Certified copies of these tests shall be furnished upon request.

68	Siemens Electrical Products and Systems	CSI Section 16470
	Specification Guide