This specification applies to earth-leakage circuit-breakers for use on both direct and alternating current systems at low or medium voltages. An earth leakage circuit-breaker intended for use in a direct-current circuit shall be deemed suitable for such use if the earth leakage tripping coil opens the circuit-breaker under the conditions set out in Clause 7 when D.C. voltages are applies, and if it otherwise conforms with the requirements of this specifiaction.
