Mending a mains fuse
General advice
- The fuse box or consumer unit is normally located next to the electricity meter.
- Fuses usually blow because:
- a circuit has been overloaded because too many appliances are being used at the same time; or
- an appliance is faulty.
- Always replace a cartridge or fuse wire with one of the correct rating:
- 5 amp for lights
- 20 amp for immersion heater
- 30 amp for sockets and cooker
- Sometimes the cooker cartridge will be 45 amp.
- Mark the name of each circuit on the inside of the fuse cover.
What to do
You need:
- torch
- screwdriver with an insulated handle, and
- fuse wire or cartridge fuse of the correct rating.
To replace a cartridge or fuse wire
- Switch off the mains switch and unplug all appliances.
- Unscrew the cover and pull out each fuse holder to check which has blown.
- If it is a rewirable fuse, loosen the retaining screws at either end, remove any old wire and feed new wire of the correct rating through the holder and around the screws. Tighten up the screws at both ends.
- If a cartridge fuse, take out the old cartridge and fit a new one into the holding clips, and replace fuse holder.
- Switch the mains back on and check that all circuits are working.
- Plug in each appliance one at a time to check if any is faulty and blows the fuse again If this happens the appliance is faulty and you should get it repaired by a qualified electrician or service engineer.
- Screw the cover to the fuses back in place.
