scope:

This standard applies to a.c. circuit-breakers designed for indoor or outdoor installation and operation at frequencies up to and including 60 Hz on systems having voltages above 1000V. It applies only to three-pole circuit-breakers for use in three-phase systems and single-pole circuit-breakers for use in single-phase systems. Two-pole circuit-breakers for use in single-phase systems are subject to agreement between manufacturer and user. It also applies to the operating devices of circuit-breakers and their auxiliary equipment. However, a circuit-breaker with a closing mechanism for dependent manual operation is not covered by this standard, as a rated short-circuit making-current cannot be specified, and such dependent manual operation may be objectionable because of safety considerations. This standard does not cover circuit-breakers intended for use on motive power units of electrical traction equipment; these are covered by the IEC Publication 77: Rules for Electric Traction Equipment. Circuit-breakers for use with overhead lines which include series capacitors are not within the scope of this standard. This standard is not necessarily applicable to circuit-breakers for special conditions, for example, those produced by two earth faults on two different phases one of which occurs on one side of the circuit-breaker and the other on the other side.