Covers items of switchgear located outdoors and either mounted on poles or structures in the run of overhead lines or as open terminal equipment within substations. Some circuit breaker equipments may require to be fitted with auto reclosing facilities. Equipment is to have a rated voltage of up to 36 kV three phase 50 Hz for use on systems with the neutral point earthed solidly, or through a resistor or reactor of low impedance or through an arc suppression coil.