Subclause 1.1 of IEC 62271-1:2007 is not applicable, and is replaced as follows.
This part of IEC 62271 applies to three-pole operated units for distribution systems that are
functional assemblies of a circuit-switcher and current-limiting fuses designed so as to be
capable of:
– breaking, at the rated recovery voltage, any load or fault current up to and including the
rated short-circuit breaking current;
– making, at the rated voltage, circuits to which the rated short-circuit breaking current
applies.
They are intended to be used for circuits or applications requiring only a normal mechanical
and electrical endurance capability. Such applications cover protection of HV/LV transformers
for instance, but exclude distribution lines or cables, as well as motor circuits and capacitor
bank circuits.
Short-circuit conditions with low currents, up to the fused circuit-switcher rated take-over
current, are dealt with by supplementary devices (strikers, relays, etc.), properly arranged,
tripping the circuit-switcher. Fuses are incorporated in order to ensure that the short-circuit
breaking capacity of the device is above that of the circuit-switcher.
This standard applies to fused circuit-switchers designed with rated voltages above 1 kV up to
and including 52 kV for use on three-phase alternating current systems of either 50 Hz or
60 Hz. Comparison with other existing switching devices is provided in Clause 8.
Devices that require a dependent manual operation are not covered by this standard.
Fuses are covered by IEC 60282-1.
Earthing switches forming an integral part of a circuit-switcher are covered by IEC 62271-102.
Installation in enclosure, if any, is covered either by IEC 62271-200 or by IEC 62271-201.