What are Residual Current Devices?

A residual current device (RCD) is a safety switch that helps protect you and your family.

When an RCD detects a problem with your power supply, it switches the power off within 10 to 50 milliseconds to prevent electric shock.

Under RCD regulations, all residential homes sold or leased in Western Australia must have a minimum of two RCDs protecting all power point and lighting circuits.

All RCDs have a test button that should be pressed every three months. Pushing the test button simulates a fault and indicates whether or not the RCD is operating correctly. Electric clocks and timers will require resetting after each test.

If you own a residential property and do not intend to sell or lease it, you are not required to have RCDs installed. However, Horizon Power strongly recommends that you consider this potentially life-saving investment.

Remember to use a licensed electrical contractor when installing new or additional RCDs.

Electrical contractors must display their licence number on their advertising, including vehicles and stationery, so remember to check these before an electrical contractor starts work at your premises.

You can check whether an electrical contractor has the necessary qualifications by visiting the EnergySafety website at and following the link to the Licensing Information System.


Horizon Power acknowledges the Traditional Custodians throughout Western Australia and their continuing connection to the land, waters and community. We pay our respects to all members of the Aboriginal communities and their cultures; and to Elders past, present and emerging.

Aboriginal and Torres Strait Islander people are advised that this website may contain images, names or voices of deceased people.