RESIDUAL Current Devices (RCDs), also known as Safety Switches, are located in distribution boards to prevent deaths from electrocution.
However, the mere presence of RCDs is no guarantee of electric shock prevention. If the switch fails or takes too long to trip, the victim could be subject to a fatal shock.
There are certain measures which can increase the operational efficiency of these switches. The Australian Standard 3760 in-service safety inspection testing and tagging of electrical equipment section outlines regular testing procedures and intervals needed to maintain the fast and safe operation of RCDs.
Technicians can ensure power is quickly cut off within a vital timeframe of someone receiving a shock. This is tested via a regular millisecond ‘trip-time test’.
Other tests stipulated by the standards include regular ‘push button’ tests that should be performed by the user between trip-time tests. These tests prevent grime, dust and sand from building up and affecting the mechanical operation of the switch.
This can be a vital procedure, because many RCDs on switchboards jam in the ‘On’ position when load tested. These push button tests are especially essential on tradesman’s power boards, which are exposed to a variety of contaminants and debris.

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