scope:

This standard applies to a.c. air-break circuit.breakers for operation at 50 Hz or 60 Hz, having a rated voltage not exceeding 440 V (between phases) a rated current not exceeding 125 A and a rated short-circuit capacity not exceeding 25 000 A. These circuit-breakers are intended for the protection against overcurrents of wiring installations of buildings and similar applications. This standard gives additional requirements for single- and two-pole circuit-breakers suitable for operation with direct current, having a rated d.c. voltage not exceeding 220 V for single-pole and 440 V for two-pole circuit-breakers, a rated current not exceeding 125 A and a rated d.c., short-circuit capacity not exceeding 10.000 A