Most homes have a row of switches in the meter box that rarely get a second look. One or more of them is likely a safety switch, also called a residual current device or RCD. These small devices cut the power when electricity leaks somewhere it should not, such as through a person. Testing them takes a few minutes and is one of the simplest safety jobs around the house.
Advice on testing differs a little between states and regulators. Western Australia and Queensland recommend testing every three months, while Energy Safe Victoria advises testing every year. Rules about how many safety switches a home must have also vary. The points below draw on guidance from state electrical safety regulators.
What a safety switch does
Circuit breakers and fuses protect wiring from too much current, which can cause overheating and fire. They do not protect people directly. The WA Government notes that the current needed to kill a person is reached well before a fuse blows or a circuit breaker operates. A safety switch works differently, by detecting current leaking out of the circuit and turning the power off.
The Queensland electrical safety regulator says a safety switch will turn off the electricity in your home within milliseconds of a fault. The WA Government describes RCDs as the single most effective measure against electrocution, serious electrical injury and electrical fire. Some safety switches are separate devices. Others are built into a circuit breaker, which the WA Government calls a combined circuit breaker and RCD.
A safety switch only protects the circuits connected to it. The Queensland regulator recommends fitting safety switches to all circuits, including power points, lighting, air conditioning, the stove, hot water and pool equipment. If you have added solar, ask an electrician how those circuits are protected. Our article on the benefits of installing solar panels for your home covers the wider picture.
Finding the safety switches in your meter box
Open the switchboard and look for switches with a button marked “T” or “Test”. The WA Government notes the button can be any shape, colour or size. There may be one, two or several of them. The same guidance suggests testing only if you feel confident and the meter box is in good condition, and calling a licensed electrician if it is not.
Western Australian homes need at least two RCDs on the main switchboard, and more may be needed. A licensed electrical contractor works out the right number and rating for each home. Energy Safe Victoria notes that many older properties do not have safety switches at all. If yours has none, a licensed electrician is the person to install them.
How to test a safety switch
The Queensland regulator sets out a simple method. First, tell everyone in the house, because the power will go off. Then press the Test button on each safety switch in turn. The switch should trip to off straight away, often with an audible clunk.
Next, walk through the house and check which lights and appliances have gone off. Anything still running is not protected by that switch. Write it down so you can ask an electrician about it later. A note kept inside the meter box door can help anyone who tests the switches after you.
Reset the switch by lifting or twisting it back to the on position. The Queensland guidance suggests waiting 2 to 3 minutes before restoring power to a fridge or air conditioner. Reset the clocks on ovens and microwaves while you are there. Then check that everything has come back on as normal.
When the test fails
If the switch does not flip to off when you press Test, it is faulty. The same applies if it will not stay on after you reset it. In either case the WA Government says to call a licensed electrical contractor. Faulty RCDs in rental homes must be replaced straight away under the WA guidance.
Remembering to test
The hardest part is remembering. The Queensland regulator suggests tying the job to your quarterly electricity bill or rates notice, or setting a calendar alert. In WA the advice is to test every three months or as often as the manufacturer recommends, whichever is more frequent. Pick a routine that suits your household and stick with it.
Safety switches in rentals and when selling
Rules here depend on your state. In Western Australia, landlords must install RCDs in rental switchboards under the Electricity Regulations. Tenants are advised to test them every three months and tell the property manager if one does not work. RCDs must also be installed at the switchboard before guests stay in a short stay rental.
Selling a home in WA brings its own requirement. RCDs must be properly installed to protect all power point and lighting circuits before the land title transfers. If two or more are missing, a licensed electrical contractor must install them. Other states have their own rules, so check with your local regulator before listing a property.
Outdoor power, kitchens and portable options
Kitchens, bathrooms, laundries and gardens are where water and electricity meet most often. The WA Government lists power point RCDs for bathrooms and workshops, which you can spot by a test button on the faceplate. Portable RCDs plug into a power board or extension lead to protect outdoor power tools and appliances. They are handy for jobs like hedge trimming or pressure cleaning.
Garden lighting and outdoor power points feature in many new garden designs, as our look at the newest innovations in landscaping shows. Any new fixed wiring outside should be done by a licensed electrician. Even a modest garden can include safe outdoor power, and our tips for landscaping on a limited budget cover where to spend first. Ask your electrician which safety switch covers the new circuit before the job is signed off.
The same thinking applies indoors. New kitchen lighting, such as the options in our article on under cabinet lighting in your kitchen, sits close to sinks and kettles. Have it installed by a licensed electrician and ask which safety switch protects it. Then add it to your list of things to check when you next press the Test button.
Frequently asked questions
How often should I test my safety switch?
Western Australia and Queensland recommend every three months. Energy Safe Victoria advises testing every year. In WA the guidance is to follow the manufacturer’s instructions if they call for more frequent testing. Testing every three months covers all of these recommendations.
Is a safety switch the same as a circuit breaker?
No. A circuit breaker protects wiring from too much current, while a safety switch detects current leaking from a circuit and cuts the power. Some devices combine both jobs in one unit. You can usually tell a safety switch by its Test button.
Can I install a safety switch myself?
No. Safety switches must be installed by a licensed electrician or electrical contractor. The same applies to fixing any fault found during testing. Your job as a homeowner is to press the Test button and report any problems.
What if some lights stay on during the test?
That circuit is not protected by the switch you are testing. It may be covered by another safety switch or by none at all. Test each switch and note what goes off each time. An electrician can then advise whether more safety switches are needed.
This article is general information only. Electrical rules differ between states and change over time. For anything beyond pressing the Test button, speak with a licensed electrician.
