This Standard specifies requirements for high voltage circuit-breakers and disconnectors, connected to three-phase, high voltage, power reticulation systems in underground coal mines, and controlling single outlet or multiple outlet circuits at voltages up to and including 12 200 V a.c. This Standard also includes the necessary provisions for isolation, safety earthing and, where applicable, facilities for regulatory authority inspection and testing requirements.NOTE: High voltage circuit-breakers and disconnectors are generally used on three-phase systems with nominal voltages of 6600 V and 11 000 V and may require approval by the relevant regulatory authority. Enquiries concerning approval may be made to the following: Department of Minerals and Energy, N.S.W.Department of Resource Industries, Qld Department of Mines, Tas.Department of Mines, W.A.Department of Mines and Energy, S.A.Department of Industry, Technology and Resources, Vic.