A safety switch (also known as an RCD or residual current device) trips when it detects current leaking to earth, which could indicate an electrical fault that may cause electric shock. The most common causes are a faulty appliance, damaged wiring, moisture in an outlet, or a worn-out safety switch. You can often identify the cause by unplugging all appliances and resetting the switch, then reconnecting devices one at a time. If the switch trips with nothing plugged in, there is likely a wiring fault and you need a licensed electrician.
What to do right now
- 1
Turn off all circuits protected by the safety switch
At your switchboard, turn off all the circuit breakers that are protected by the tripping safety switch. Then reset the safety switch itself.
- 2
Turn circuits on one at a time
Turn each circuit breaker on one at a time, waiting a few seconds between each. When the safety switch trips, the last circuit you turned on contains the fault.
- 3
Isolate the faulty appliance
On the faulty circuit, unplug every appliance and device. Reset the safety switch and circuit breaker. Plug appliances back in one at a time. The one that causes the trip is the faulty appliance — remove it from service.
- 4
Call a licensed electrician if the switch trips with nothing plugged in
If the safety switch trips with all appliances disconnected, the fault is in the wiring itself. This requires a licensed electrician to diagnose using an insulation resistance tester and repair the fault.
When to call an emergency electrician
- ⚠️The safety switch trips with all appliances unplugged — indicating a wiring fault
- ⚠️You cannot identify which appliance is causing the trip
- ⚠️The safety switch trips immediately upon resetting, every time
- ⚠️The safety switch is old and may be faulty itself (test button does not work)
- ⚠️Multiple safety switches are tripping at the same time
- ⚠️There is a burning smell or visible damage at the switchboard
How much does it cost?
The cost to diagnose and fix a tripping safety switch in Australia ranges from $150 to $400 for a simple appliance-related issue. If the fault is in the wiring, costs increase to $300–$800 depending on the extent of testing and repair needed. Replacing a faulty safety switch (RCD) itself costs $180–$400 including parts and labour. A full switchboard safety upgrade with new RCDs can cost $800–$2,500. After-hours callout surcharges of $100–$200 typically apply.