Free Electrical Tool
Safety Switch Coverage Checker
Safety switches (RCDs) reduce the risk of electric shock — but only on the circuits they cover. Answer a few questions to see how well your home is protected.
Coverage matters as much as having one
Plenty of Sydney homes have a safety switch on one part of the board and nothing on the rest. Because an RCD only reduces risk on the circuits wired through it, the power points and appliances left on ordinary breakers or fuses still carry more risk. Our guide on whether you need a safety switch walks through what proper coverage looks like, and a switchboard upgrade is the usual way to close the gaps.
If there are children in the home, the socket circuits are the ones that matter most — read our notes on child electrical safety at home. Whatever your board looks like, pressing the test button every few months is a safe habit worth keeping, and you can always book a licensed electrician for a proper check.
Frequently asked questions
How often should I test my safety switch?
Press the test (T) button on each safety switch roughly every three months. It's a simple, safe check anyone can do — the switch should trip and cut power to that circuit. If it doesn't trip, or the power doesn't come back cleanly when you reset it, stop and have a licensed electrician inspect it.
Does a safety switch protect the whole house?
Not always. Older installs sometimes have one safety switch on part of the board, or none at all, while other circuits run on ordinary breakers or fuses. Only the circuits wired through an RCD are protected. An electrician can tell you exactly which circuits are covered and fit RCDs on those that aren't.
Do ceramic fuses have safety switches?
No. Ceramic rewireable fuses only protect against overload and short circuit — they don't provide the earth-leakage protection a safety switch (RCD) gives, which is what reduces the risk of electric shock. Boards on ceramic fuses are generally upgraded so the circuits people touch have RCD protection.
Can a safety switch prevent electric shock?
A safety switch reduces the risk by disconnecting power very quickly when it detects current leaking to earth — but no device can guarantee you won't be injured. It's one important layer of protection alongside sound wiring and safe habits. Treat electricity with respect and never work on fixed wiring, switchboards or the meter yourself.