If you live in an older home your switchboard may still have semi-enclosed rewireable fuses.
These fuses are ceramic plug-in units on the switchboard. They have a length of fuse wire connected between two screws on the contacts of a fuse holder and operate in an overload or short-circuit current.
From time to time these fuses can blow and the following steps must be used to safely replace the wire.
Switch the power off from the appliance being used and unplug it.
Turn off the main switch and any other control switches (such as hot water).
Use the correct rated fuse wire for the size of the cable in the circuit it protects.
The fuse rating is generally stamped on the outside of each fuse holder or marked on the switchboard near the fuse base.
Never use an oversize fuse wire as it can cause damage to the electrical installation wiring or start a fire.
Put the correctly rewired fuse into its holder and turn on the main power switch.
If the fuse blows again with the electrical equipment unplugged the fault may be in another electrical appliance or a fault in the wiring. You should then call a licensed electrical contractor.
Common risk with plug-in ceramic fuses.
- Replace burnt wire with oversized wire – cause of over heating of the electrical wires and can start a fire.
- Not switching OFF main switch – internal contact inside the fuse holder stay live. Touching these contacts will cause electric shock.
- Fuse holder or fuses themselves gets broken – exposed live part – can cause electric shock.
- Bad connection between the fuse and its housing due to replacing wires many time – cause of fire inside switchboard.
- Bad connection between wires and fuse holder due to uptight screws – cause of fire inside switchboard.
In some houses Ceramic fuses were replaced with pug-in Circuit breakers. While this procedure avoid the need of replacing burnt wire, except point 1 above all other point are relevant with same level of danger.