Why does my safety switch keep tripping? (And when to call an electrician)

Quick answer: A safety switch (RCD) trips when it detects electricity leaking somewhere it shouldn't, often through a faulty appliance, water getting into an outdoor power point or light, or damaged wiring. It's doing its job: protecting you from an electric shock. The most common cause is a faulty appliance, which you can often find yourself by unplugging everything and switching things back on one at a time. If it keeps tripping with everything unplugged, there's a burning smell, or it won't reset, call a licensed electrician.

By Jordan Grant, licensed electrician (ACT & NSW)

⚠️ Stop and call an electrician straight away if you notice a burning smell, scorch marks, buzzing or crackling, a hot switchboard or power point, or if anyone has had a shock. Don't keep resetting the switch.

Safety switch vs circuit breaker: what tripped?

Open your switchboard and look for the switch that's in the "off" or middle position:

• Safety switch (RCD): usually has a "T" or "Test" button. It trips on earth leakage, meaning electricity escaping to earth, which could be through a person.

• Circuit breaker: no test button. It trips on overload or short circuit: too much current on that circuit, or a fault.

Knowing which one tripped narrows down the cause.

The most common reasons a safety switch trips

1. A faulty appliance. This is the big one. Kettles, toasters, washing machines, fridges, dishwashers, heaters and old power tools are frequent culprits. A worn heating element or water inside the appliance can leak current.

2. Water and moisture. Rain getting into an outdoor power point, garden light or external fitting. If it trips when it rains, this is likely.

3. Damaged wiring. A nail or screw through a cable, rodent damage in the roof, or old perished insulation.

4. A faulty power point or light fitting, especially old or outdoor ones.

5. Lots of small leakages adding up. In a big home with many appliances on one safety switch, normal tiny leakages can combine and trip it. Newer boards spread circuits across more safety switches (or individual RCBOs) to prevent this.

6. A worn-out safety switch. Less common, but RCDs can fail. They should be tested regularly.

Safe checks you can do yourself

Only do these if there's no burning smell, heat or visible damage:

1. Unplug everything on the affected circuits. Switch appliances off at the wall and pull the plugs out.

2. Reset the safety switch (flip it back to "on").

3. If it stays on, plug appliances back in one at a time, waiting a minute between each. When it trips again, the last thing you plugged in is your likely culprit. Stop using it and get it repaired or replaced.

4. If it trips straight away with everything unplugged, turn off all the circuit breakers, reset the safety switch, then turn the breakers back on one at a time. The breaker that trips it points to the faulty circuit. Leave that one off and call an electrician.

5. If it only trips when it rains, note which outdoor fittings are on that circuit. An electrician will need to look at them.

Don't open power points or switchboards, use anything that got wet, or hold the switch on. It's tripping for a reason.

When to call an electrician

• It trips with everything unplugged

• It won't reset at all

• It trips repeatedly, even after you've removed the suspect appliance

• It happens when it rains

• Your switchboard has old ceramic fuses or only one safety switch for the whole home

• There's any smell, heat, sound or scorch mark

We'll find the fault with proper insulation and leakage testing, fix it, and make sure your safety switches are actually working.

Prevent it: test and upgrade your safety switches

• Press the test button on each safety switch every few months. It should trip instantly; reset it after.

• Older homes often have just one safety switch, or none on some circuits. Modern boards protect every circuit, and spreading circuits across several RCDs or RCBOs means one fault doesn't black out the whole house.

• Landlords and businesses: periodic RCD testing keeps records for compliance and catches failing switches.

Need help now?

Home Plus does emergency call-outs across Canberra and Queanbeyan, 7am to 10pm, 7 days. A licensed electrician will find the fault, make it safe and fix it properly.

Emergency electrician · Call 0433 976 398

"Always my first point of call for an electrician. He resolves problems efficiently." — Stephen C., Google review ★★★★★