Short answer: A safety switch trips when it detects current leaking to earth. The most common cause is a faulty appliance, followed by water getting into an outdoor power point or light, and damaged or ageing wiring. To find the culprit, unplug everything on that circuit, reset the switch, then plug things back in one at a time. If it trips with everything unplugged, or won’t reset at all, the fault is probably in the fixed wiring, and that’s a job for a licensed electrician.
A tripping safety switch is annoying, but it’s doing exactly what it’s designed to do. Something is leaking current, and the switch is stopping it from finding a path through a person. The good news is that many trips are caused by a single faulty appliance you can find yourself, safely, in a few minutes.
First: is it the safety switch or a circuit breaker?
Open your switchboard and look at what’s switched off.
- Safety switch (RCD or RCBO): has a T or Test button, often marked 30mA. Trips on earth leakage.
- Circuit breaker: no test button. Trips on overload (too many appliances) or a short circuit.
If it’s a plain circuit breaker, the cause is usually too much load on one circuit, such as a heater, kettle and air fryer at once, or a short circuit in an appliance or the wiring. If it’s a safety switch, follow the steps below.
Step-by-step: find the faulty appliance
Safety first: don’t touch the switchboard with wet hands, don’t open any covers inside the board, and if you see scorching, smell burning or hear crackling, stop and call an electrician.
- Turn off and unplug everything on the affected circuit or circuits. If one safety switch covers all your power points, that means everything plugged in around the house. Don’t forget the fridge, the washing machine, outdoor gear and anything hidden behind furniture.
- Reset the safety switch. Push it firmly back to ON.
- If it trips straight away with everything unplugged, the fault is in the fixed wiring, a hardwired appliance (like an oven, cooktop, hot water system or air conditioner) or an outdoor fitting. Stop here and call an electrician.
- If it stays on, plug appliances back in one at a time, switching each on and waiting a minute or so.
- When it trips again, the last thing you plugged in is the likely culprit. Leave it unplugged, reset the switch, and check the rest.
- Get the faulty appliance checked or replaced. Don’t keep using it.
Some appliance faults only show up when an element heats up or a motor runs. Kettles, toasters, washing machines, dishwashers and fridges often need a full cycle to trip.
The usual suspects
Appliances
Appliances with heating elements or motors are the most common cause: kettles, sandwich presses, irons, heaters, washing machines, dishwashers, fridges and freezers. Old extension leads and cheap power boards are also common culprits.
Water
If your safety switch trips when it rains, suspect moisture. Outdoor power points, garden lights, sensor lights and exposed junction boxes are the usual entry points. Leaking roofs can also drip into light fittings. In older Inner West terraces, rear courtyards and side passages often hide old outdoor outlets that aren’t properly weatherproof.
Fixed wiring and hardwired appliances
If the switch trips with everything unplugged, the problem could be damaged cable (from drilling, nails or rodents), ageing insulation, a failing oven element, a hot water system fault, or an air conditioner. These need an electrician with an insulation resistance tester to track down. Our electrical fault finding service covers this.
Nuisance tripping on a shared RCD
In older switchboards, one RCD can protect several circuits. Small leakages from lots of appliances can add up and trip it, even though no single appliance is faulty. Upgrading to more RCDs, or to RCBOs, spreads the load so one fault doesn’t take out half the house.
When the safety switch won’t reset
If the switch won’t stay on even with everything unplugged:
- There’s likely a fault in the fixed wiring or a hardwired appliance, or
- The safety switch itself has failed.
Either way, call a licensed electrician. Don’t try to bypass the safety switch. It’s protecting you from a fault you can’t see.
When to call an electrician straight away
- the switch trips with everything unplugged
- you smell burning, see scorch marks, or hear buzzing or crackling
- you got a shock or tingle from an appliance, tap or metal fitting
- it keeps tripping after you’ve removed the obvious appliances
- the switch is hot to touch or physically damaged
If you get a tingle from a tap or metal fixture, stop, don’t touch it again, and report it. Ausgrid treats shocks and tingles as electrical emergencies and asks you to call 13 13 88 (or 000 if anyone is in danger). See what to do in an electrical emergency.
Safety switch driving you mad? We find and fix tripping faults across the Inner West, including Leichhardt, Marrickville, Ashfield and Petersham. Call 0421 772 661 and tell us what’s tripping and when.
Frequently asked questions
Why does my safety switch trip when it rains?
Water is getting into something electrical, usually an outdoor power point, garden or sensor light, or a junction box. A leaking roof dripping into a light fitting can also cause it. An electrician can find and weatherproof the fault.
Can a fridge trip a safety switch?
Yes. Fridges and freezers are common causes, often because of a failing compressor, a defrost heater fault or moisture. Test it last when you plug things back in, and don’t leave it off too long.
Is it safe to keep resetting a tripping safety switch?
Not repeatedly. Each trip means current is leaking somewhere. Find and remove the cause, or call an electrician, rather than resetting it over and over.
Can a safety switch go faulty?
Yes. They’re mechanical devices and can fail with age. If it won’t reset with nothing connected, or doesn’t trip when you press the test button, have it replaced.