SECTION : 2.1
All boards combination of 14 & 16 SWG sheet steel, free standing, extensible, totally enclosed, dust tight, vermin-proof cubicle, flush dead front and of modular construction suitable for 3 phase 415V 4 wire 50 Hertz system. All boards accessible from the front or as shown on Drgs and specified in the equipment data sheet, for the maintenance of switch fuses, busbars, cable terminations, meters etc. Cables capable of entering the board both from top as well as bottom. All panels machine pressed with punched openings for meters etc. All sheet steel passed through 7 tank rust removing process of degreasing, acid pickling, phosphating etc. The panels finished with powder coating of approved colour applied over a primer. Engraved plastic labels provided indicating the feeder details, and capacity and danger signs.
The boards shall accommodate air insulated bus bars, air circuit breakers, mccb’s switch fuse units with HRC fuses, starters, necessary meters, relays, contactors etc. as required and arranged in suitable tiers. All breakers and switch fuses suitably de-rated taking into account specified ambient temperature and ruling temperature inside the cubicle.
The switch board fully compartmentalised in vertical tiers housing the feeder switches in totally enclosed independent compartments. Each compartment self sufficient with switch unit, fuses, contactors, relays, indicating lamps and an inter-locked door with facility for padlocking.
Each switch or MCCB or ACB shall have provision for locking in the OFF position for life safety. Each feeder must terminate in an independent labelled terminal block. Strip type terminal block accommodating several feeders together is not acceptable. Pressure clamp type terminals suitable for aluminium wires may be used upto switches of 25A and cable lugs for higher ratings. All terminations shrouded in an approved manner. The entire enclosure shall meet with IS: 2147/1962. Feeder connections of solid insulated copper/aluminium wires or strips with bimetallic clamps wherever required and if insulated, the insulation able to withstand the high temp at the terminals. Internal wiring, bus bar markings etc. shall conform to IS:375/1963. Internal wiring shall have terminal ferrules.
Main switch should be at an easily accessible height and the highest switch operating handle should not be over 1.85M from floor level. Cable glands shall form part of the switch board.
Bus bars three phase and neutral and of copper/ Aluminium as specified and shown on drawings and rated for a temperature rise of 35 deg C over the ambient temperature specified, (IS:8084-1976). Neutral bars may be of one half the size of the phase bars or as shown on drawings. The main horizontal bus bars of uniform cross section and rated for the incoming switch. The vertical bus bars for the feeder columns will be rated at 75% of aggregate feeder capacity and uniform in size. Bus bars and interconnections taped with PVC colour coded tape to prevent bar-to bar accidental shorts. Each bus bar directly and easily accessible on removal of the front cover. Bus bars totally enclosed, shrouded and supported on non-hydroscopic insulator blocks to withstand thermal and dynamic overloads during system short circuits.
Protective earthing provided as shown on drawings or as follows:
|Phase Conductor||Protective conductor|
|upto 16 sqmm||equal size|
|16 to 35 sqmm||16 sqmm|
|over 35 sqmm||50% of phase conductor|
In case of dissimilar materials the Protective Earth Conductor suitably sized for equal conductance.
Protective earthing of each switch connected to the earth bar.
All panels supported on MS channels incorporated in the panel during the fabrication. All such supports prime coated with two finish coats after completion of the work. All panels touched up for damaged painting.
Fabrication drawings of all panels approved by the Consulting Engineers before fabrication.
Testing & Inspection
All switch boards factory inspected before finishing and dispatch unless waived.
Certificate for all routine and type tests for circuit breakers in accordance with the IS:2516-1963 furnished. In addition, all panels meggared phase to phase and phase to phase neutral, using a 1000V meggar with all switchgear in closed position. The meggar value should not be less than 2.5 mega-ohms between phases and 1.5 mega-ohms between phase and neutral.
All field tests witnessed by Consultants and recorded unless waived. All Panels to be tested at manufacturing site prior to dispatch in presence of Rep. of Owner & Consultant, for which all expenses to be borne by the Contractor.
|LIST OF RECOMMENDED MAKES OF MATERIALS|
Low Voltage (433V) SYSTEM:
|MAKES OF EQUIPMENT.|
|1B||APFC Panel Manufacturers||SAMCON|
|2||Air Circuit Breakers||Siemens / ABB /Schneider/L&T|
|3||Moulded Case Circuit Breakers||Siemens / ABB /Schneider/L&T|
|4||MCB’s, ELMCB and ELCB’s||Siemens / ABB /Schneider/L&T|
|7||CT Test Link||Elmex type CST / CONNECTWEL|
|8||Protection relays||Alstom / C & S / PC / Siemens|
|9||Meters||CONZERVE / SECURE|
|10||Control switches.||Alstom / Kaycee / L & T.|
|11||Control Fuses||Siemens / BUSMAN|
|12||Indicating Lamps, Push Buttons.||TEKNIK/ESSEN.|
|13||Contactor||Siemens / L & T /Schneider/ABB|
|14||Terminal block||Elmex type CST / equivalent|
|15||Wires||Finolex / Polycab/ RR|
|16||Auto Transfer Switch||ASCO/ ABB|
|17||Copper Flexible Cables.||Finolex / Polycab/ RR / MUNISU|
|18||Rotary switches||Kaycee, SALZER|
|19||Load Manager||CONZERVE, SECURE, Trinity|
|20||Isolation Transformer||SAMCON OM / PRAGATI|
|21||APFC Relay||L & T / Trinity/ Beluk|
|22||Capacitors||L&T /Epcos/ Ducati|
|23||Protection Relays||JVC /L & T/ C&S|
|24||Motor Protection Circuit Breakers||Siemens / Schneider /L & T/ABB|
IP - Code Of Protection
Degree of Protection for the Electrical Enclosures As per IEC 529 & BS 5490
First Numeral- Protection Against Solid Particles
|0||No protection||Object not protected|
|1||Protection against objects of size 50 mm in Dia or greater e.g Hand||Any Object having 50mm size should not enter|
|2||Protection against objects of size 12.5mm in Dia or greater e.g Fingers||Any Object having 12.50mm size should not enter|
|3||Protection against objects of size 2.5mm in Dia or greater e.g Tools||Any Object having 2.50mm size should not enter|
|4||Protection against objects of size 1mm in Dia or greater e.g Small Wire||Any Object having 1 mm size should not enter|
|5||Dust Protected||Harmful Dust Particles Protected|
|6||Dust Proof||Completely Protected Against Dust particles|