1、Standard forInstalling Medium-VoltageMetal-Clad SwitchgearNECA 430-2006Published byNational Electrical Contractors AssociationAMERICAN NATIONAL STANDARDStandard forInstalling Medium-VoltageMetal-Clad SwitchgearNECA 430-2006An AmericanNational StandardPublished byNational Electrical Contractors Assoc
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3、th their supportingstructures, enclosures, conduc-tors, electrical interconnections,and accessories.Vacuum Circuit A mechanical switching device Breaker capable of making, carrying,and breaking currents undernormal circuit conditions andalso, making and carrying for aspecified time and breaking cur-
4、rents under specified abnormalcircuit conditions such as thoseof a short circuit or groundfault, that uses vacuum as theinterrupting medium. Vacuumcircuit breakers can be of thefixed-mounted or drawout type.Voltage See Potential Transformer (PT).Transformer*Not a part of this Standard.3 a73Installin
5、g Medium-Voltage Metal-Clad Switchgear NECA 4303.1 Deliverya) Coordinate the arrival of switchgear so that theinstallation of equipment pads and foundations iscomplete and ready to receive switchgear upon deliv-ery.b) Upon delivery of equipment and accessories,visually inspect packaging for physical
6、 damage.Carefully unpack protective crates and packing suffi-ciently to inspect for concealed damage resultingfrom shipping and handling. If damage hasoccurred, notify the shipper and the manufacturer inwriting immediately.c.) Circuit breakers are typically shipped in the“Closed” position. After rem
7、oving packing material,open the circuit breaker by pushing the manual tripbutton located on the front of the circuit breaker.Check the indicator flags on the front of the circuitbreaker to ensure that the circuit breaker is “Open”and the springs are “Discharged.”d) Compare equipment and accessories
8、received withthe bill of materials to verify that the shipment iscomplete. Verify that equipment and accessoriesreceived conform with approved submittals and man-ufacturer quotations. If the shipment is not complete,notify the manufacturer in writing immediately.e) Uncrate station control power batt
9、eries and placeon trickle chargers immediately upon receipt.f) If equipment and accessories are to be storedprior to installation, restore original packing materi-als and protect from exposure to environmental con-ditions. When conditions permit, leave the packingmaterials intact until equipment and
10、 accessories areready for installation. Follow all instructions in themanufacturers instruction manuals for proper pro-tection and storage of the equipment.3.2 Handlinga) Switchgear is typically shipped as completelyassembled as possible, although several shippingsplits may be necessary to facilitat
11、e handling largerswitchgear line-ups. Circuit breakers are typicallyshipped in individual containers, but may be shippedinstalled in switchgear. Follow all instructions in themanufacturers instruction manuals for proper han-dling of the equipment.b) Switchgear is typically large, bulky equipmentweig
12、hing several thousand pounds or more. Thepacking list will provide the actual weight of eachitem. Handle equipment and accessories in accor-dance with manufacturer recommendations in orderto avoid injury to personnel and damage to equip-ment. Verify that the lifting capacity of the handlingequipment
13、 is more than the weight to be moved.Obtain the shipping weight and the type of truckmaking the delivery prior to receiving the shipment.Delivery on an open truck to the job site is recom-mended. Provide suitable protection against theweather, in accordance with the information in themanufacturers m
14、anuals and drawings.c) Handle switchgear carefully, especially consideringthe instrument panel on the front of the switchgearthat may contain delicate instruments, relays, meters,switches, and control that are easily damaged. Avoidimpact, jolting, jarring, rough handling, etc.d) Indoor switchgear sh
15、ipping sections are typicallyequipped with lifting lugs or provisions at the top ofthe sections, while outdoor switchgear shipping sec-tions typically have lifting provisions at the bottom3. Delivery, Handling, and Storagea73 4of the section. Switchgear is intended to be handledusing a crane . Do no
16、t handle switchgear or circuitbreakers using a forklift.e) Unload switchgear shipping sections from thedelivery truck using a crane (See Figure 1). Attach alifting cable at each of the four (4) lifting points tolift and move sections, and use load-rated slings orcables with safety hooks or shackles.
17、 Use spreaderbars to maintain proper angles for lifting and to pre-vent slings or cables from rubbing against equip-ment. Rig the lifting slings or cables so that the min-imum angle between lifting slings or cables and thetop of the equipment is 45, and the maximum inte-rior angle is 90. Interior an
18、gles greater than 90apply greater inward pressure of lifting lugs whichcan damage or dislodge lifting lugs from switchgear.Remove and discard lifting lugs after the equipmenthas been placed in position. Screw bolts back intoplace to cover the mounting holes.f) Preferably, use the circuit breaker tru
19、ck for elevat-ing and transporting circuit breakers. Use manufac-turer-provided structural lifting points when hoistingor lifting circuit breakers. If it is necessary to lift cir-cuit breakers with a hoist or crane, verify that it iscapable of supporting a minimum of 1,000 pounds,and use four 4-1/2
20、inch (115 mm) diameter hooksrated a minimum of 500 pounds each. Attach liftinghooks to the lifting provisions located on the sideframe members of the circuit breakers. Use a spread-er that is wider that the circuit breaker to preventslings from contacting interrupter supports. Do notlift circuit bre
21、akers by placing forklift bars beneaththe circuit breaker frame.g) If crane facilities are unavailable, use rollers underthe shipping skids or consult the manufacturer for rec-ommendations. Maintain shipping skids to protectswitchgear from being distorted or damaged duringhandling. Do not handle swi
22、tchgear directly on rollers.h) Preferably, install switchgear in the final installa-tion location upon delivery. When switchgear isstored in other than the final installation location,coordinate staging to minimize handling.i) When handling circuit breakers on a smooth, flatsurface, roll and maneuve
23、r circuit breakers by grasp-ing the top edge of the front cover. Do not use themain contacts of circuit breakers or primary leadassemblies as lifting handles.3.3 Storagea) Store switchgear indoors in a clean, warm, dry,well-ventilated room with a moderate temperatureranging between 40F and 100F. Out
24、doorswitchgear is not considered weatherproof untilinstallation is complete.b) Store switchgear in its permanently installed loca-tion whenever possible.c) Protect switchgear from rain, snow, dirt, and dust,until final assembly is completed, especially consideringswitchgear bus runs and openings in
25、shipping splits.d) Protect switchgear and circuit breakers from cor-rosive gases or fumes, dust, foreign objects, androdents. Moisture in combination with cement dustis very corrosive.e) Store switchgear in a monitored area to discour-age vandalism and theft, and out of the way of con-struction traf
26、fic.f) Lubricate important parts such as jack-screws,gears and chains of racking mechanisms, linkages,and moving parts with manufacturer-recommendedheavy oil or grease to prevent corrosion or rust.g) Maintain switchgear internal temperature approxi-mately 10F above ambient temperature during storage
27、.Installing Medium-Voltage Metal-Clad Switchgear NECA 4305 a73Spreader BeamLifting Straps45 minimum angleFigure 1a73 6NECA 430 Installing Medium-Voltage Metal-Clad Switchgear1. Temporarily energize switchgear space heatersfrom an outside source. Open the control powertransformer secondary disconnect
28、ing means,remove the primary fuses, and install an out-of-service tag before energizing space heaters froman outside source to prevent backfeeding themain bus through the control power transformer.2. Use temporary heating source with switchgearthat is not equipped with space heaters. Maintaina minim
29、um of 200 Watts of heat per circuitbreaker and primary cable compartment.Remove all cartons and other miscellaneousmaterials packed inside units before energizingheaters. Do not use sources of heat that generatesmoke, grease, or other products of combustionthat can deposit carbon on insulation, resu
30、lting intracking, corona, and eventual insulation failure.h) Spot check insulation-resistance of such parts asoperating coils every six weeks during storage. If anyreadings are low, the affected parts should be driedout before they are placed in operation.i) Store circuit breakers separately from sw
31、itchgear,unless recommended to be stored in switchgear bymanufacturer.j) Unsatisfactory storage conditions can cause dam-age to the insulation and sensitive electrical and/orelectronic components. Inspect switchgear regularlyduring storage for signs of damage. Consider the fol-lowing during storage:
32、1. Support the foundation. To prevent distortion,the storage foundation must be level and flat. Ifthe base is made of a material other than con-crete, elevate switchgear above ground level tominimize the effects of ground moisture. If piermounting is required, consult the manufacturerfor recommendat
33、ions.2. Ventilation. If extended storage is required,ensure that switchgear ventilation openings areunobstructed and provide free circulation of air.3.3.1 Storing circuit breakersa) Store circuit breakers in a clean, dry area protect-ed from damage, corrosion, and construction debris.b) Install circ
34、uit breakers in their permanent loca-tion as soon as possible. Install circuit breakers inswitchgear equipped with space heaters only afterheaters are operational.c) Inspect circuit breakers regularly for rust andoverall condition when stored for prolonged periods.Manually operate circuit breakers p
35、eriodically whenstored for any length of time, and lubricate in accor-dance with manufacturer recommendations whennecessary.d) Clean and dry out circuit breakers before placinginto service when stored in unfavorable atmosphericconditions. Check insulation resistance, in additionto other manufacturer
36、s recommended checks andinspections before energization.3.3.2 Storing Batteriesa) Store batteries indoors, in a dry place.b) Batteries that have been shipped dry and chargedshould have the seals inspected when they are receivedat the site. Any seals that are damaged should berenewed per the manufact
37、urers instructions.c) Lead-acid batteries that have been shipped wetshould be handled as follows:1. Electrolyte level should be inspected when bat-teries are received at the site. Electrolyte shouldbe added to the proper level, if any has been lost.2. Three months after date of shipment from thefact
38、ory, and every three months thereafter, batter-ies should be given a refreshing charge to restorethe voltage to 2.15 volts per cell and the specificgravity to 1.21 at 77F (25C). The charging rateshould not exceed the manufacturers recom-mended value. Do not overcharge batteries.3. Other types of bat
39、teries that have been shippedwet should be handled per the manufacturersinstructions.4.1 General Requirementsa) Install switchgear in accordance with drawings,specifications, approved shop drawings, and manu-facturer recommendations.b) Do not install equipment beneath catwalks orother elevated perso
40、nnel access routes.c) Maintain a minimum overhead clearance of 6 feet(1.8 m).4.2 Site Selectiona. Check that adequate ventilation exists thatlimits ambient temperature around the switchgear to104F (40C). NOTE: If ambient temperatures exceed104F (40C) switchgear must be de-rated. Check thatsupplied a
41、ir is clean, dry, and filtered.b) Check that adequate lighting is provided for boththe front and back aisle spaces around the switchgear,in addition to convenience receptacles in both areasfor electrical hand tools.c) Check that sufficient clear aisle and working spaceis available around the switchg
42、ear to fully open doorsfor removing circuit breakers and transformers, con-sidering equipment and components that may berecessed-mounted on the cubicle door. Provide suffi-cient working space at the rear of the switchgear toinstall conductors and to perform inspections andmaintenance that may be nec
43、essary.d) Check that switchgear is protected against waterdamage. Check that water, sewer, and steam lines donot pass directly over or in close proximity toswitchgear. Check that adequate floor drainage existsin switchgear rooms.e.) Check that the site can support the installedswitchgear and the equ
44、ipment necessary to move theswitchgear into position.f) Check that switchgear seismic withstand capabili-ties are compatible with the installed location andcomply with contract requirements. Check the pro-posed installation pathways, before ordering shippingsplits, so they arrive in sections or leng
45、ths that can bemoved past obstructions in the pathways.4.3 Conduitsa) Install conduits in accordance with drawings,specifications, and manufacturer shop drawings.Carefully coordinate conduit locations to preventmechanical interferences. Conduits must enter fromeither the top or the bottom of the cab
46、le compart-ment.b) Install conduits stubbed up in concrete prior toplacing concrete. Stub up conduits a maximum of 1inch (25 mm) above the level of the switchgear floor.Ensure that there is no mechanical interference withconduits and switchgear floor steel.c) Install top entrance conduits after swit
47、chgear isset in place.4.4 Switchgear FoundationSwitchgear is typically designed to be installed onmanufacturer-supplied base channels. Switchgearmay be designed to be installed on base channels. Ifbase channels are used, they should be installed, lev-eled in accordance with manufacturers requirement
48、s,and grouted in the concrete. Provide a smooth, hard,level floor surface under and in front of switchgear tofacilitate installation and removal of circuit breakers.4. Site Preparation7 a73a73 8NECA 430 Installing Medium-Voltage Metal-Clad Switchgeara) Install concrete equipment pads in accordancewi
49、th drawings, specifications, and manufacturer rec-ommendations.b) Install base channels in the locations detailed inthe base plan drawings. Ensure that the channels liein a flat, level plane in accordance with the manufac-turers instructions to ensure proper alignment andto prevent distortion of the switchgear cubicles andskeleton. Ensure that non-supporting areas of thefoundation are lower than the tops of the steel chan-nels.c) Ensure that an aisle is provided in front of theswitchgear mounting pad, flush with and finished tothe same tolerance as the mounting pad, to
