NATIONAL ALUMINIUM COMPANY LIMITED - Rites

The MCCBs shall be suitable for panel mounting and shall be fixed type. All live parts shall be
enclosed in moulded case and all contacts shall be silver plated. The breakers shall be trip trip-free
and with quick make & break operating mechanism. The MCCBs sha shall be provided with
ambient temperature compensated bi bi-metal metal overload releases and a magnetic short short-circuit
release with inverse time characteristic. Releases shall be either static or microprocessor
based.
The operating handle shall be included with mod module ule door such that the door can be opened
only with the breaker in the “OFF” position. The MCCB handle after the breaker tripped due to
a fault shall occupy an intermediate position. The breaker shall be capable of interrupting a full
fault current corresponding onding to the fault level specified.
MCCBs shall have a breaking capacity of 50kA at 415V. Current limiting MCCBs are not
permitted.
The LDB shall be consisting of following feeders:
Incomer : 2 Nos. each of 600 A MCCB with over current and earth pprotection.
Bus coupler : 1 No. of 600 A MCCB
Outgoing : 125 A MCCB
63 A MCCB – 10 Nos.
SUB LIGHTING DISTRIBUTION BOARD (SLDB)
415V, 3 phase, 4 wire, 125/63A (as applicable), indoor/outdoor type (as applicable) generally
conforming to IS 13947 and IS 8623 as applicable.
The SLDB shall comprise of one number of incoming TPN MCCB, three nos. of DP MCBs, and
requisite number of outgoing SPN MCBs (as specified) and adequately rated bus bars. The
SLDBs shall also have timer, contactors, A/M switch, etc as per requirement. The enclosure
class of SLDB shall be IP 54. The terminals of MCCB shall be fully shrouded. The boards shall be
of industrial, totally enclosed dust dust-proof, proof, wall mounted, sheet steel cubicle design. The
thickness of the sheet steel shall be 2 mm. The boards shall have welded back and sides and
gasketted hinged door at the front with door handle and suitable locking devices. For boards
with incoming isolating switch the access to the operating handle shall be from the front of the
cubicle without opening the front door. Operating knobs of outgoing MCBs shall be accessible
only after opening the front door of the cubicle. Protective insulated cover plate shall be
provided inside the cubicle to shroud all the live parts with only the operatin operating knobs of the
MCBs protruding outside the cover plate. The boards shall also be dust dust-proof in door-open
position. Adequate space shall be provided within the boards to facilitate termination of
incoming and outgoing cables. The boards shall be factory wir wired ed and assembled. Where
specifically called for, the boards shall be of special weather weather-proof proof design suitable for outdoor
installation.
Technical Specification:Sec-6, Electrical
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