3.6.17 Earth Leakage Circuit Breaker (ELCB) Earth leakage circuit breakers (ELCB) as per the current ratings and sensitivity as shown on the drawings shall be provided in the distribution board. The ELCB shall be suitable for operating at temperature ranging between - 10ºc to + 60ºC ambient and calibrated at least at 40ºC ambient. Wherever required and applicable, the upstream protection device of the ELCB shall be selected taking in to account the manufacturer de-rating factors as per the ambient temperature. The earth leakage circuit breaker (ELCB) shall comply with the applicable IEC standards. The ELCB shall have a rated operational voltage of 240 V/415V AC, 50 Hz as defined by IEC standards. The ELCB shall be modular, compact and din-rail mount design. The ELCB shall be easy clip on type and shall fit on to the standard din rail or to the purpose made brackets inside the distribution board. The ELCB shall be of matching design with the manufacturer MCB. The ELCB shall be easily removable from the busbar without disturbing the adjacent installed switching devices in the distribution board. The ELCB shall be available in 2-pole and 4-pole versions. The physical dimensions of the ELCB (within its own version) shall be same for all ELCB rating ranging from 25 A to 125 A for interchangeability and standardization purpose. There shall be a test button on the front face of the ELCB to test the earth leakage trip function. The test trip circuit shall be electrically operated. Residual current release of the ELCB shall be an electromagnetic device operating without any auxiliary source of supply. ELCB shall be of automatic resetting type. All poles of the ELCB shall operate simultaneously for closing, opening and tripping. The ELCB shall be protected against nuisance tripping due to transient over voltages. The ELCB shall be actuated by toggle. The operating toggle shall be on the first pole of the ELCB for both 2-pole and 4-pole version. The isolation function shall be certified by tests guaranteeing the mechanical reliability of the position indication system, the absence of leakage currents and over voltage withstand capacity between the upstream and downstream connections. Isolation shall be with positive break indication. The number of operation cycle (0-C) of the ELCB shall be at least equal to 20,000. The ELCB shall be provided with an electromagnetic device for residual current release and shall combine the functions of control and automatic breaking of a circuit against an insulation fault that occurs between the phase & earth. The ELCB shall also perform the function of isolation. With addition of certain accessories to the ELCB, it shall be possible to perform the functions of control. The ELCB shall be designed for both vertical and horizontal mounting, without any adverse effect on electrical performance. It shall be possible to supply power either from upstream or downstream side. The ELCB shall be available in ratings from 16 A to 125 A and the sensitivity range from 30 mA to 300 mA without any change in dimension or appearance. The ELCB sensitivity shall be of fixed type. Unless specified otherwise, the ELCB at the main incoming circuit of the distribution board shall be 100 mA sensitivity. Unless specified otherwise, the ELCB shall be instantaneous release type. Wherever discrimination with a downstream ELCB is required, the ELCB shall be with selective release. The ELCB shall be designed to enable safe on-site installation of various auxiliaries such as shunt release, under voltage release and fault trip/on–off indication switches where ever required. It shall be possible to fit all the auxiliaries on to an ELCB. All the auxiliaries shall be of the snap-in type and fitted with terminal blocks matching the ELCB design and finish. All the auxiliaries shall be common for the entire range. Page 103