scope:

This part of IEC 62271 is applicable to AC circuit-breakers designed for indoor or outdoor installation and for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 1 000 V to be tested with direct testing methods. NOTE - In a direct testing method one source is used to supply the voltage and current during the making and breaking tests. This part of IEC 62271 is not applicable to: - circuit-breakers with a closing mechanism for dependent manual operation; - circuit-breakers intended for use on motive power units of electrical traction equipment; these are covered by IEC 60077 [1] 1; - generator circuit-breakers installed between generator and step-up transformer; these are covered by the IEC 62271-37-013 [2]; - self-tripping circuit-breakers with tripping devices that cannot be made inoperative during testing. Tests on automatic circuit reclosers are covered by IEC 62271-111 [3]; - tests to prove the performance under abnormal conditions that are not described in this part are subject to agreement between manufacturer and user. Such abnormal conditions are, for example, cases where the voltage is higher than the rated voltage of the circuit- breaker, conditions which may occur due to sudden loss of load on long lines or cables.