What the safety switch is telling you
A safety switch, or RCD, watches the current flowing out on a circuit and coming back. Energy Safe Victoria says it detects a problem that may put people at risk and turns the power off within 0.03 of a second. When a heater trips it, some current is escaping through the heater's element, casing or cord, which is exactly the fault the safety switch is there to catch.
Overloading is a different fault. Too many heaters, kettles and dryers on one circuit usually trips a circuit breaker rather than the safety switch, although on many newer boards one device, an RCBO, does both jobs. Either way, the trip is telling you something.
Common causes
Elements wear out, and as their insulation breaks down they start leaking current to earth. A heater stored all summer in a damp garage or shed can take on moisture, and dust builds up inside fan heaters. A cord crushed under furniture, kinked or chewed, or a plug with a cracked body, can do it too. An oil column heater with any sign of oil on its fins or the floor is finished.
Power boards bring their own trouble. A heater draws a lot of current for hours at a time, and sharing a power board with other appliances can make the board and its plug hot. Plug heaters straight into a wall outlet.
Is it the heater or the circuit?
Unplug the heater and reset the safety switch once. If the power stays on, and the heater trips it again from a power point on a different circuit, the heater is the problem. If the safety switch trips with the heater unplugged, or won't reset, the fault is in the wiring or another appliance, and Energy Safe Victoria advises calling a licensed electrician. Our team tracks down which circuit and which item is at fault.
A heater that has tripped a safety switch shouldn't go back into use without a check, and a cheap older heater usually isn't worth repairing. If a living room or study relies on portable heaters every winter, a fixed reverse-cycle unit is the better long-term answer: it moves 3 to 5 units of heat for each unit of electricity, while a standard electric heater makes about 1.
What you can safely do now
- Unplug the heater, then reset the safety switch once.
- If the safety switch won't reset or trips again with the heater unplugged, leave it off and book a licensed electrician.
- Check the cord and plug for cracks, scorch marks or crushed sections, and stop using the heater if you find any.
- Plug heaters straight into a wall outlet, not a power board or extension lead.
Services that can help
Read more in our guides
Related questions
- Why does my heater smell when I turn it on for the first time in winter?A dusty, slightly burnt smell on the first run of the season is usually dust burning off the heat exchanger, coil or element, and it fades.
- Why does the kettle or toaster trip the safety switch?Usually the appliance has a fault that lets a little current leak to earth.
- Why does my washing machine or dishwasher trip the safety switch?Water and worn heating elements are the usual causes.
- Is a safety switch power point the same as a safety switch on the board?No.
Sources for this answer
3 sources, with the date each was checked
- 1.Energy Safe Victoria: monitors the flow of electricity through a circuit detects a problem that may pose a risk to personal safety turns the power off within 0.03 of a second always has a test button and '30ma' printed on them. Accessed 30 September 2026.
- 2.Energy Safe Victoria: Locate your electricity box outside your home and check whether the safety switch has tripped. If it has tripped, reset the switch. If the switch won’t reset, call a licensed electrician. Accessed 30 September 2026.
- 3.Energy Rating (GEMS Regulator / DCCEEW): Reverse cycle air conditioners are much more efficient at heating than standard electric heaters (bar heaters, convection, or radiant heaters). ... During the normal operating range in Australia for every unit of… Accessed 30 September 2026.
General information for homes in Victoria. Every installation is different, so treat this as a starting point. Where this answer refers to Victorian safety or rental rules, the sources above have the current requirements.