Why does my safety switch keep tripping

It usually happens at the worst time. You are halfway through dinner, or it is pouring rain at midnight, and the power drops out. You go to the switchboard and find the safety switch has tripped. You reset it, and it trips again. What is going on?

The short answer: a safety switch trips when it detects current leaking to earth. It is designed to do exactly that, because leaking current can mean someone is getting a shock. So a trip is a message worth paying attention to.

The most common causes

A faulty appliance

This is the most frequent culprit. Kettles, toasters, washing machines, dishwashers, fridges and old power tools can develop leakage as their insulation ages or moisture gets in. The trip often happens when that appliance switches on.

Water and moisture

Outdoor power points, garden lights and pool equipment are exposed to rain, sprinklers and condensation. If trips happen after rain or a heavy dew, a wet outdoor fitting is a strong suspect. Coastal homes from Windang to Gerroa see more of this because salt speeds up corrosion in fittings.

Hot water systems

A failing electric hot water element can cause leakage. If trips happen at a regular time, such as when off peak hot water switches on overnight, that is a clue.

Damaged wiring

A nail or screw through a cable, rodent damage in the roof, or deteriorated insulation in older homes can all cause leakage. These faults need an electrician to find and fix.

Too many appliances on one RCD

Every appliance leaks a tiny amount of current in normal operation. When lots of them share one safety switch, the small amounts can add up. Spreading circuits across more RCDs helps.

How to narrow it down safely

• Unplug every appliance on the affected circuits
• Reset the safety switch
• If it holds, plug appliances back in one at a time, waiting a minute between each
• If it trips when a particular appliance goes back in, leave that appliance unplugged and have it checked or replaced
• If it trips with everything unplugged, the fault is likely in fixed wiring or a hard wired appliance, and it is time to call an electrician

Our guide how to reset a tripped safety switch walks through the reset itself.

What not to do

Never hold a safety switch on, tape it, or ask anyone to bypass it. If it will not stay on, it is protecting you from something. Do not open power points or light fittings to look for the fault yourself.

When to call an electrician

• The safety switch trips with every appliance unplugged
• You smell burning or see scorch marks
• Trips happen with no pattern you can identify
• Hard wired equipment like an oven, hot water system or pool pump seems involved

Intermittent faults can be frustrating to track down. Customers have told us we fixed a problem other electricians could not resolve, and that usually comes down to methodical testing: isolating circuits one by one, insulation resistance testing, and checking outdoor and hidden fittings rather than guessing.

Is it worth adding more safety switches

If one RCD protects your whole house, a single faulty appliance can knock out everything, including your lights. Adding RCDs or upgrading to RCBOs keeps faults contained. See our safety switches page and what is an RCD and how many do I need.

If your safety switch will not stay on, call or text Kalani on 0424 400 346. We are open 24 hours for emergency call outs across Shellharbour, Wollongong and Kiama. Our emergency electrician page has more.