A safety switch is a device that quickly switches off the electricity supply if an electrical fault is detected, to minimise the risk of electricity-related fires, electric shock, injury and death.
By law, safety switches protecting power points and lighting circuits must be installed in all new homes and in buildings where electrical circuits are altered or added. This law was introduced in 1991, so if your home was built before this time, it may not be protected by safety switches.
Safety switches are also required for power outlets supplying caravans or similar accommodation in caravan parks.
If you are unsure whether your home has a safety switch, contact a licensed electrician for advice or to have one installed.
How safety switches work
When a person makes direct contact with electricity, it is directed away from its main path in the electrical circuit and instead goes through the person’s body to earth. A safety switch can detect the change in the electrical circuit and switches the power off in as little as 0.3 seconds.
Fuses and circuit breakers protect against short circuits and current overloads, but only safety switches protect people from electric shock.
Safety switches are only a back-up. They may not protect all wiring and electrical appliances and will not prevent all electric shocks.
Types of safety switch
Knowing the different types of safety switch, their purpose and the protection they provide will help you choose a safety switch that best suits your needs.
The three main types of safety switches are:
- switchboard safety switches
- power point safety switches
- portable safety switches.
Switchboard and power point safety switches must be installed by a licensed electrician. Make sure the electrician gives you a certificate of compliance within thirty days of completing the installation, to show the work has been done safely.
Switchboard safety switches
Switchboard safety switches are installed on individual circuits and are used to protect:
- selected electrical circuits throughout the house
- electrical appliances and extension cords connected to the protected power points.
Switchboard safety switches must be installed by a licensed electrician.
If an electrical fault occurs on a circuit with a switchboard safety switch, the switch will turn off the electricity supply to that particular circuit. Appliances and lighting connected to other circuits will keep operating.
Power point safety switches
A power point safety switch replaces an existing power point. These switches protect appliances and power cords plugged into the switch, and may protect other electrical wiring and power points on the same circuit.
Power point safety switches must be installed by a licensed electrician.
To maximise the protection on a particular electrical circuit, the power point safety switch should be installed at the first power point after the switchboard.
Portable safety switches
Portable safety switches are essential protective devices for people working with power tools and other electrical appliances where there is no access to switchboard or power point safety switches. Portable safety switches will only protect you from faults in the equipment directly plugged into them.
To use a portable safety switch, plug it directly into the power point and plug the appliance into the safety switch socket.
How to test a safety switch
You should test your safety switches a couple of times a year to ensure they are in good working order. An easy way to remember is to test them when you change your clock for daylight savings.
You can test a safety switch by pressing its 'test' or 'T' button. The safety switch should immediately trip to the 'off' position. You will then need to return the switch to the 'on' position.
If your safety switch does not trip to the 'off' position after you have pressed the 'test' button, turn off the power immediately and call a licensed electrician.
Safety switches in workplaces must be tested and records kept in accordance with the South Australian Occupational Health Safety and Welfare Regulations.
The video below shows you how to test your safety switch.
Nuisance tripping, faults and resetting safety switches
If a safety switch has disconnected the power (tripped), it may be due to a temporary fault, lightning or nuisance tripping. Resetting the switch should restore the power supply.
If you cannot reset a safety switch after it has tripped, you may have a faulty appliance connected to the circuit, or there may be a wiring fault. In this case, switch off and unplug the appliance that you think is faulty. You should now be able to reset the safety switch and restore the power. If you are not sure which appliance is faulty, switch off and unplug one, then try to reset the safety switch. Do this for each appliance on the circuit until you find the one that causes the safety switch to trip.
If you are unable to reset the safety switch or can’t work out which appliance is causing a problem, call a licensed electrician to find and correct the fault.