What a safety switch does
A safety switch, also called a residual current device or RCD, constantly compares the current going out on the active wire with the current coming back on the neutral. If some of it is leaking to earth, for example through a faulty appliance or someone touching a live part, the switch trips and cuts the power almost instantly.
That’s different to a circuit breaker, which protects the wiring from overloads and short circuits. A breaker won’t stop a shock. A safety switch is designed to. Many modern boards use RCBOs, which combine both jobs in one device for each circuit.
Does your home have enough protection?
Plenty of homes have one safety switch covering the power points and nothing on the lighting, air-con, oven or hot water. Older homes might have none at all. Open your switchboard and look for devices with a “Test” or “T” button. If you can’t find any, or you’re not sure what’s covered, we can check for you.
Current Wiring Rules (AS/NZS 3000) call for RCD protection on the final circuits in homes when new work is done, and when a switchboard is replaced. In practice that means most homes with older boards will need a switchboard upgrade to get full coverage, because there’s simply no room to add safety switches to the old enclosure.
Safety switches in rental properties
If you’re a landlord in Queensland, you have obligations around safety switches in rental homes. The Electrical Safety Office at electricalsafety.qld.gov.au sets out the detail, and it’s worth reading if you own an investment property. NSW has its own rules through NSW Fair Trading for properties across the border in the Tweed and Byron areas.
We regularly help landlords and property managers get rentals up to standard. Our rental property electrical service covers safety switches, smoke alarms and general safety checks, with paperwork you can keep on file.
Why safety switches trip
A safety switch that trips is usually doing its job. Something on that circuit is leaking current to earth, and the switch has spotted it. The most common causes we find are:
- A faulty appliance, often a kettle, toaster, fridge or washing machine
- Water getting into outdoor power points, garden lights or sensor lights
- Damaged or deteriorated wiring in older homes
- Pool pumps and equipment, especially after heavy rain
- Too many appliances with small normal leakage sharing one RCD
A quick first step is to unplug everything on the circuit, reset the switch, and plug things back in one at a time. If it trips again on a particular appliance, that appliance is likely the problem. If it trips with nothing plugged in, it’s a wiring fault and needs an electrician. Our blog post on why your safety switch keeps tripping goes into more detail, and our fault finding service will track down the cause.
Testing your safety switches
Every safety switch has a test button. Pressing it simulates a fault and should trip the switch straight away. We recommend doing this every three months. If it doesn’t trip, the device needs replacing.
The push button only tells you the switch trips. It doesn’t tell you how quickly. When we test safety switches, we use a proper RCD tester to measure the trip time and current, which confirms the device will react fast enough in a real fault. Safety switches are mechanical devices and can stick or slow down over the years, especially in humid coastal homes, so a proper test is worth doing every now and then. This is part of every installation and every electrical safety inspection we do.
What installation involves
If your board has room and is in reasonable condition, adding safety switches can be a fairly quick job. We fit the new devices, reorganise circuits so they’re sensibly spread across the RCDs, and test everything. Spreading circuits out matters, because it means one fault doesn’t plunge the whole house into darkness.
We also check how your circuits are grouped. In some older homes, one safety switch covers every power point in the house, so a single faulty toaster can knock out the fridge, the freezer and the home office at once. Splitting circuits across two or more devices keeps the rest of the house running while you sort out the problem.
If the board is old, full or unsafe, we’ll recommend replacing it instead. We explain why, show you what we found, and give you a written quote for both options where that makes sense.
What affects the cost
The cost depends on how many circuits need protection, whether your existing board can take new devices, and whether we find existing faults when the safety switches go in. An old outdoor light or a damaged cable that was quietly leaking will show up as soon as it’s protected, and it needs fixing before the switch will hold. We always give you an upfront written quote and talk to you before doing anything extra.