Earthing Switches

Earthing switches are safety devices which are integral parts of circuit breakers.  When a circuit breaker is removed and racked out, the sections of the bus bar adjacent to the circuit breaker are automatically earthed by means of these switches.

This protects the maintenance personnel from accidental voltages.    The closing action of the earthing switch is of snap action type.  Earthing switches are usually dimensioned to withstand short circuit currents.  Earthing switches can also be motorised.

Earthing switches are usually used in conjunction with isolators. When the isolator isolates the circuits, the earthing switches make contact with the busbar and discharge any charges which may have accumulated there.