What each one is watching
A circuit breaker measures how much current flows. When a heater, kettle and dryer on one circuit add up to more than the cable is rated for, or a fault causes a short, the breaker switches off before the cable overheats. It ignores small leaks: the current that can seriously hurt a person is far too small to trip a breaker.
A safety switch, also called an RCD, looks at something else: whether all the current that goes out on a circuit comes back. Energy Safe Victoria says it monitors the flow of electricity through a circuit and turns the power off within 0.03 of a second when it detects a problem that may put someone at risk. A safety switch on its own won't trip for an overload.
Why a home needs both
Energy Safe Victoria describes safety switches as an additional form of protection used with circuit breakers and fuses, and says they won't prevent every shock. The Wiring Rules call for safety switch protection on every final sub-circuit in a home, and when a switchboard is replaced, every final sub-circuit has to have it. Since 29 March 2023, Victorian rentals must have modern switchboards with both circuit breakers and safety switches.
Telling them apart on your board
Safety switches have a test button and 30mA printed on them, and one often covers several circuits. Circuit breakers have no test button, and each protects a single circuit. An RCBO combines both jobs in one device for one circuit, so a leak trips only that circuit rather than a whole group. If your board has ceramic fuses and no test buttons anywhere, it has no safety switches.
Energy Safe Victoria recommends pressing the test button on each safety switch every three months. If the power doesn't go off, the switch may have failed and needs a licensed electrician.
Services that can help
Read more in our guides
Related questions
- How do I tell which switch has tripped on my switchboard?Open the switchboard door and look along the rows of switches.
- Is a safety switch power point the same as a safety switch on the board?No.
- Why does my washing machine or dishwasher trip the safety switch?Water and worn heating elements are the usual causes.
- Why does the kettle or toaster trip the safety switch?Usually the appliance has a fault that lets a little current leak to earth.
Sources for this answer
5 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: Clause 2.6.3.2.2 requires all final sub-circuits in a domestic installation be protected by a residual current device (RCD). A hot water service is included in this requirement Accessed 30 September 2026.
- 3.Energy Safe Victoria: If a switchboard is required to be replaced then as per clause 2.6.3.2.5 (Alterations to installations and replacement of switchboards) of AS/NZS 3000: RCD’s are required on all final sub-circuits. Accessed 30 September 2026.
- 4.Consumer Affairs Victoria: The electrical safety rental minimum standard commenced on 29 March 2023. Rental properties must have modern switchboards, with circuit breakers and electrical safety switches installed. Electrical safety switches are… Accessed 30 September 2026.
- 5.Energy Safe Victoria: Follow these steps to check your safety switch every three months: Press in the test buttons on each safety switch which will cut the power and trip the switch into the off position. You may hear a clunking sound. If… 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.