4.4 RESIDUAL CURRENT OPERATED CIRCUIT BREAKERS
Residual current operated circuit breakers without integral overcurrent protection (rccb) and residual current operated circuit breakers with integral overcurrent protection (rcbo) shall be current operated functionally independent of line voltage type, suitable for use on a 240/415 V, 50 Hz. a.c. system and up to an ambient temperature of 40 0C. Rccb shall comply with IEC 61008-1 and 61008-2-1 and rcbo shall comply with IEC 61009-1 and 61009-2-1. They shall be of either two-pole or four-pole type as indicated in the Drawings and/or Bill of Quantities.
The rated current and the rated residual operating current of the rccb or rcbo shall be as specified in the Drawings and/or Bill of Quantities. For rcbo, protection against overcurrent shall of B-type with Class 3 energy limiting characteristic complying with IEC 60898, and shall have breaking capacity of not less than 6 kA. Rccb and rcbo shall provide resistance against nuisance tripping due to an impulse voltage or transient overvoltage. Test push button and visual indication for ‘ON’ and ‘OFF’ or ‘|’ and ‘0’ shall be provided. They shall be equipped with screw clamping type of cable terminals, which shall be covered by moulded phonolic plastic with knockouts for cable entry.