Fuses and Circuit Breakers

The switchboard protects your home’s electrical wiring system. It contains the mains power switch, as well as a number of fuses, or circuit breakers. Each fuse or circuit breaker corresponds to a different area of wiring in your home. If an electrical fault occurs, the fuse will blow or the circuit breaker will trip. The power to that area of the house will be shut off, preventing overloading and fires.

The main difference between circuit breakers and fuses is that circuit breakers can be reset. Once a fuse blows it must be replaced. Always turn off the mains power switch, all appliances and lights that are on that fuse before you replace it. Always replace a fuse with the correct current rating. A fuse with too high a current rating will cause excessive current to flow through the circuit, leading to overheating and possibly fire. If a fuse keeps blowing call a licensed electrician.

If possible, have a licensed electrician replace the fuses in your switchboard with plug-in circuit breakers of the same rating, as these are safer to use and do not require replacing.

How to Replace a Fuse

Follow this guide when replacing some types of fuses:

  • Turn off the main power switch at the switchboard.
  • Look inside the switchboard for a list of the equipment or circuits each fuse controls. Usually one fuse controls a certain area of the house, such as the kitchen, or certain types of equipment, like lighting.
  • If you can’t tell which fuse has blown, pull out, inspect, and replace each fuse, one at a time.
  • Once identified, switch off lights and unplug all appliances on the faulty circuit.
  • Replace the fuse wire. There are a number of different types of fuses. If you are not sure, the best way to replace a fuse is to examine one of the intact fuses in your switchboard and copy the way the wiring runs in the fuse carrier.
  • Make sure you use the correct current rating wire. The current is generally indicated on the front of the fuse carrier.
  • Lighting circuits typically use 5 amp wire, but not greater than 10 amp wire.
  • Socket outlets use 10 amp wire, but not greater than 15 amp wire.
  • Large appliances, such as electric stoves, may use a larger size.
  • Make sure no excess wire is sticking out of the fuse carrier.
  • Replace the fuse carrier and turn on the mains power switch.
  • Check all appliances, light fittings and cords that were in use when the circuit failed. Replace or repair faulty equipment. Also check that the fuse did not blow due to overloading the circuit.
  • If the fuse blows again, call a licensed electrician.

How to Check Your Circuit Breaker
If your power goes off because your circuit breaker has tripped, look for the lever in the ‘off’ position, or where the button has popped out.

To restore power:

  • Switch off lights and unplug all appliances on the faulty circuit.
  • Push the operating lever to the ‘on’ position, or push in the button on the circuit breaker.
  • If the circuit breaker continues to trip, call a licensed electrician.