480V Metal-Enclosed SwitchgearSelection and Application Guide

SGSA-3061C (Nov.1998)

ContentsGeneral .......................................................................................................1

Construction Details ................................................................................ 2-4LV Power Circuit Breakers ...................................................................... 5-9VT, CPT, CT Data ...................................................................................... 10LV Power Circuit Breakers Ratings ..................................................... 11-13Weights and Dimensions ................................................................... 14-15Floor Plans / Side Views ..................................................................... 16-17Guide Form Specifications .................................................................. 18-19

Siemens low-voltage metal-enclosedswitchgear is used in electric power dis-tribution systems for the control and pro-tection of circuits and equipment. Theswitchgear employs drawout type lowvoltage power circuit breakers describedon pages 5-13.

LV switchgear is typically installed in:J Industrial Plants for power and

lighting networks and feeders, powergeneration and other auxiliaries, and toprovide power for machine tools andmaterial handling equipment drivers.

J Utility and Co-generation Facilities for motor control centers to protectand distribute power to electricaldevices such as blowers, compres-sors, fans, pumps, and motors.

J Commercial and ResidentialBuildings for protection and distri-bution of power for lighting, elevators,air conditioning, blowers, fans,motors, and pumps.

Available Types:J Type R indoor (NEMA 1)J Type SR outdoor walk-in (NEMA

3R)Low-voltage switchgear can be appliedon distribution systems with:J 3-phase, 3- or 4-wire feedersJ 50 or 60HzJ Voltages of 208, 240,480, or 600 voltsJ Currents up to 5000 amperesCircuit breakers may be either manuallyor electrically operated, fused or unfused.The following designations are used:J RL Standard InterruptingJ RLE Extended InterruptingJ RLI High InterruptingJ RLF Fused TypeSiemens Static Trip III trip units are pro-vided on all low voltage power circuitbreakers, except non-automatic circuitbreakers. All circuit breakers are ULListed. See Tables 4.10 and 4.11 for cir-cuit breaker ratings.

Industry StandardsTypes R and SR switchgear with powercircuit breakers are designed, tested andconstructed in accordance with:J ANSI C37.20.1 Metal-Enclosed

Low Voltage Power Circuit BreakerSwitchgear

J ANSI C37.50 Test Procedure forLow Voltage AC Power CircuitBreakers Used in Enclosures

J ANSI C37.51 Conformance Testingof Metal-Enclosed Low Voltage ACPower Circuit Breaker SwitchgearAssemblies

J Applicable standards of IEEE andNEMA

J Applicable requirements of theNational Electric Code (NEC)

J UL 1558 Metal-Enclosed LowVoltage Power Circuit BreakerSwitchgear

Type RL drawout circuit breakers are inaccordance with:J ANSI C37.13 Low Voltage AC

Power Circuit Breakers Used inEnclosures

J ANSI C37.16 Preferred Ratings,Related Requirements, andApplication for Low Voltage PowerCircuit Breakers and ACPower CircuitProtectors.

J ANSI C37.17 Trip Devices for ACand General Purpose DC Low- VoltagePower Circuit Breakers.

J UL 1066 Low Voltage AC and DCPower Circuit Breakers Used inEnclosures.

Features and modifications required byNEC are incorporated when the assemblyis designated as Service (Entrance)Equipment.

UL Listing (Optional)An Underwriters Laboratories listingmark (UL label) can be optionally suppliedfor each vertical section. The specificsection must contain only devices whichare UL Listed or are UL recognized com-ponents found suitable for the intendeduse. All circuit breaker drawout elementsare UL Listed.

General

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480 Volt Metal-Enclosed Switchgear

480V Metal-Enclosed SwitchgearConstruction Details

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General

GeneralThe Siemens 480 volt switchgear assem-bly consists of one or more metal-enclosed, vertical sections. Normally theend sections are designed to allow forinstallation of future sections. Each vertical section consists of up tofour individually enclosed breaker or auxil-iary compartments which are sized toprovide uniform height.Included in each assembly are variouscomponents such as circuit breakers,instrumentation and control equipment,transformers, relays, three-phase buswork, and all internal wiring, connectors,and other supporting equipment.In accordance with ANSI C37.20.1, themaximum temperature for parts that arehandled is 50C. The main bus maximumtemperature rise is 65C above 40Cambient. The temperature rise of the airsurrounding the cable connection pointsis limited to 45C above 40C ambient.

FinishDuring construction, the structural steelparts, panels, and compartments are allprepared for painting by a five-stagewash system. Standard finish color islight gray ANSI 61. If a different finishcolor is required, it is applied over thestandard finish with conventional sprayequipment and is allowed to air cure. Thecompleted finish has a nominal 2 mils dryfilm thickness.

Assembly ConstructionSiemens metal-enclosed powerswitchgear is constructed of preformed,full-depth, 14-gauge steel sheets boltedtogether and reinforced with cross-mem-ber braces to form a rigid, self-supportingcompact assembly. The top and rearplates, and side sheets are all 14-gaugesteel. When two vertical sections aremounted together, two sheets of 14-gauge steel separate adjacent circuitbreaker compartments.

Bolted steel / glass polyester compart-ments housing each power circuit break-er are mounted in the vertical section toform the switchgear assembly. This iso-lates the circuit breakers from the bus /cable section and from adjacent circuitbreaker compartments.The bus / cable section includes mainhorizontal bus, riser bus, connectionsfrom the main bus to each set of primarydisconnects, and load side copper run-back bus.Grounded metal barriers can be providedto isolate the main bus from cable con-nections. Barriers are also available toisolate the incoming line to the main cir-cuit breakers from the main load bus ofthe switchgear.

c

b

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a Inter-Unit Wiring Troughb Meter and Auxiliary Compartmentc Ventilation and Lifting Structured Telescoping Breaker Drawout Railse Ventilation Openings (RL-2000, RL-3200, RL-4000

and RL-5000)

480V Metal-Enclosed SwitchgearConstruction Details

General

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Main and Ground Bus The standard main bus is silver-platedcopper. Welded aluminum is also avail-able. Provisions for future extension ofaluminum main bus conductors includetin plated joints with high tensile strengthsteel hardware. Tin-plated copper bus isoptionally available.The main three-phase horizontal bus isarranged vertically one phase above theother with edge-to-edge alignment toprovide high, short circuit strength.Insulated main and vertical bus areoptional.Main bus ratings available are 1600,2000, 3200, 4000, or 5000 amperes con-tinuous current. A neutral bus is fur-nished when specified, and can be rated1600, 2000, 3200, 4000 or 5000 amperescontinuous current.A standard copper ground bus extendsthrough all sections. A cable lug can bemounted to the ground bus in eachsection.Minimum bus bracing is 65,000 amperesRMS symmetrical. Higher symmetricalbracings are available based on the low-est breaker short circuit rating in thegroup.Load side runbacks for feeder circuits areone-piece copper construction, are insu-lated with sleeve tubing in the main busarea, and are supported by high-strength,glass polyester moldings.

Control WiringStandard secondary and control wiring is#14 AWG extra-flexible, stranded coppertype SIS. Terminations are made withcompression-type, insulated terminals.For devices not having screw-type termi-nals, tab-type disconnects are used.

InsulationThe insulation used is Pyro-Shield, a fiber-glass-reinforced polyester material thathas high impact strength and low mois-ture absorption. Other features includehigh flame retardance, high resistance tochemical fumes, and long life at hightemperatures.

Circuit Breaker CompartmentsTypical circuit breaker compartmentsinclude primary disconnects, ground dis-connect, drawout rails, and associatedinterlocks, and secondary disconnects, ifappropriate. Telescoping drawout railsallow the breaker to be withdrawn fromthe compartment without additionalextensions or adapters. Compartmentsfor electrically-operated circuit breakersinclude secondary disconnects and con-trol circuit fuses. Up to three currenttransformers for metering or relaying canbe mounted in each compartment.Circuit breaker compartment front panelscan be used to hold a variety of auxiliarydevices such as breaker control switch-es, ammeters, and test blocks.

a Control Circuit Fusesb Ground Disconnectc Secondary Disconnectd Front Panel Devicese Primary Disconnect

f TOC Switch Operatorg Interference Interlockh MOC Switch Operatori Space Heaterj Drawout Rails

Circuit Breaker Cell Interior

OptionsSwitchgear Mounted HoistThe hoist, optional on type R indoorswitchgear, and standard on type SRoutdoor switchgear, travels along rails ontop of the switchgear to ease breakerhandling.

TOC and MOC SwitchesThe Truck Operated Cell (TOC) Switchprovides interlocking control or remoteindication of the breaker racking position.The cubicle mounted auxiliary switch orMechanism Operated Cell (MOC) switchprovides interlocking control or remoteindication based on the main contactposition (open or closed).The switches have field adjustable con-tacts for simple conversion of contactsfrom normally open (a type) to normal-ly closed (b type). Each c