scope:

This standard is applicable to mechanical switching devices designated as "circuit-breakers for equipment" (CBE) intended to provide protection to circuits within electrical equipment in the case of overload conditions. CBE's may have a switching capacity higher than required for overload conditions and may in addition have a conditional short-circuit capacity rating in association with a specified short-circuit protective device. This standard is also applicable for protection of electrical equipment in case of undervoltage and/or overvoltage. It is applicable for a.c. not exceeding 440 V and/or d.c. not exceeding 250 V, and a rated current not exceeding 125 A. This may be used as a guiding document for voltages up to 630 V a.c. This standard covers CBE's which are either intended for automatic interruption and non-automatic resetting only, or intended also for performing manual switching operations. This standard does not cover CBE's for isolating purposes, for which more stringent requirements are under consideration.