Miniature circuit breakers shall be of approved design and make. Circuit breakers shall be equipped with individually insulated, braced and protected connectors. The front face of all the breakers shall be flush with each other. The incoming MCBs shall be provided with insulator shoes.
MCBs shall be suitable for operation at 230V/415V, 50Hz supply. The MCB ratings shall be available from 0.5-125A in 1P/2P/3P/3P+N/4P versions. The rated short circuit capacity according to IS8828 shall be of 10,000A. MCBs shall be offered with either C or D tripping characteristics as per the BOQ requirements. The MCBs shall be suitable for conductor cross-sections upto 35sq mm and shall be suitable for mounting on a 35mm DIN rail. The mechanical life shall be in line with the requirements of the standards, namely IS8828.
MCB shall ensure complete electrical Isolation of downstream circuit or equipment, when the MCB is switched OFF (to be marked on the MCB in symbolic form)
IP 20 Degree of Protection shall be ensured to prevent electrical shocks by accidental touch to any live parts, by providing finger touch proof terminals.
Energy Limitation Class-3 shall be to ensure minimum let through energy in the event of a fault, for safety & longevity of downstream circuit equipment. (to be mentioned on the MCB as per standards)
Low Power Loss must be ensured i.e. MCBs should have low power loss, in any case not more than prescribed limits of standards. Energy efficient MCBs having lesser power loss than prescribed in relevant standards will be preferred.
MCBs shall have minimum 25 sq.mm. terminals for ratings below 32A, and 35 sq.mm. for ratings of 32A and above, to ensure perfect termination of connections. Terminals of MCBs shall have captive screws.
Basic technical parameters, rating, operating voltage, etc. shall be printed on front face of MCB for ease of identification. Operating knob can be sealed in ON / OFF condition without affecting any automatic tripping. Availability of Auxiliaries like Auxiliary Contact, Shunt Trip to remotely trip or indicate the circuit breaker status shall be fitted to MCB easily