What Is an RCD?
A Residual Current Device (RCD), commonly called a safety switch in Australia, is an electrical safety device that monitors the flow of electricity through a circuit and automatically disconnects the power if it detects current leaking to earth. This leakage typically means electricity is flowing through an unintended path — such as a person’s body — and the RCD trips in as little as 30 milliseconds to prevent electrocution.
Types of RCDs
There are several types of RCDs used in Australian homes and workplaces:
- Switchboard-mounted RCD — installed in the main switchboard, protects entire circuits. This is the standard type required in Australian homes.
- Portable RCD — a plug-in device used on construction sites and for outdoor power tools where fixed protection may not be available.
- Socket-outlet RCD — built into the power point itself, common in older installations or as an upgrade option.
Under AS/NZS 3000 (the Wiring Rules), all new homes must have RCD protection on all power and lighting circuits. Older homes may only have RCDs on power circuits, and some very old properties may have none at all.
State Variations
| State/Territory | RCD Requirements for Existing Homes |
|---|---|
| QLD | RCDs required on power circuits; recommended on lighting |
| NSW | RCDs required when electrical work is done on a circuit |
| VIC | RCDs required on power circuits in all rental properties |
| WA | Two RCDs required on all homes (power circuits) since 2000 |
| SA | RCDs required on power circuits |
| TAS | RCDs required on power circuits |
| ACT | RCDs required on power and lighting circuits |
| NT | RCDs required on power circuits |
How It Relates to Licence Verification
RCD installation, testing, and repair is restricted to licensed electricians. Only a licensed electrician can legally modify your switchboard, install new RCDs, or issue a Certificate of Electrical Safety. Verify your electrician’s licence through TradieVerify before any electrical work to ensure they hold the correct class of licence for switchboard work in your state.