AS 2081-1977

This specification applies to equipment for current-operated earth-fault protection, earth-fault protection, earth-fault lockout protection, earth-continuity protection and earth-fault current limitation for use in coal and shale mines. It is limited to a.c. systems supplying equipment below ground at voltages up to and including 1.1 kV, except earth-fault limitation where equipment for use with voltages up to 11 kV is covered. It includes requirements for elements that detect the faulty condition, apparatus for initiating tripping or locking-out of circuit-breaking devices, and equipment for limitation of earth-fault currents. It does not include requirmeents for the circuit-breaking devices or sensitive earth-fault protection devices of the type used for portable hand-held tools as these requirements are set out in other Australian Standards.