How to repair a fuse in a fuse box

Before you start, you should turn off all the electrical appliances and other electrical items in your home, including your lights and possibly even your boiler, as you have a blown fuse because you are either overloading your sockets or because an electrical item is broken. Please see the video below for advice on how to avoid overloading electrical sockets.

If you do not turn everything off before you start repairing the fuse, the fuse may break immediately after you turn your electricity supply on again.

How To Change A Fuse in a Fuse Box

• Turn the main fuse box off. You can usually do so by turning the main power switch to the “off” position.

• Open the cover that protects the fuse carriers, or remove this cover.

• Take out the fuse carriers and inspect them to determine which one is the broken fuse. You may be able to tell which fuse you need to replace by the presence of scorch marks, or the fuse may be visibly broken.

• If the blown fuse has affected a whole power circuit, then turn off and unplug every appliance that uses the circuit. For lighting circuits, simply turn off the light switches. Doing so means that when you fix the circuit and turn the main switch back on, the fuse will not immediately blow again.

• Remove the broken fuse wire and replace the fuse wire.

How to replace a fuse wire

• Buy a fuse wire that meets the correct amp rating.

• Loosen the terminal screws and remove the old and broken wire.

• Cut the new fuse wire so that it is long enough to wrap around both terminal screws and cross the fuse carrier.

• In a clockwise direction, wind the wire around one terminal screw.

• Tighten this terminal screw into place.

• Look at one of your working fuses to figure out how to wire the fuse up. You will have to either thread the wire through the fuse holder or pass it through the bridge. Wind the wire around the remaining terminal screw, also in a clockwise direction. The wire should be a little bit slack, as it will tighten when you screw in the remaining terminal screw.

• Tighten the final terminal screw and replace the fuse carrier.

• Close the cover and turn the main switch on again. The circuit should now be repaired.

How to replace a cartridge fuse

• Buy a cartridge fuse tester so you can check which cartridge is broken.

• Turn off the main fuse in the fuse box.

• Gently remove one of the cartridges. There may be a screw in the cartridge carriers that you have to remove.

• Test the fuse in the cartridge fuse tester.

• If the fuse works, put it back in the cartridge, put the cartridge back in the fuse box, and check the next cartridge.

• When you have discovered which fuse has blown, replace this with a new fuse. Ensure the new fuse has the same amp rating as the fuse carrier requires.

• Turn the main switch back on.

If you have a circuit breaker

Circuit breakers are far easier to fix than old-fashioned fuseboxes. It should be very obvious what fuse has tripped in a fuse box, as the switch will be in a different position from all of the other switches or will have popped out.

• Turn off all the appliances on the affected circuit.
• Switch the miniature circuit breaker on.
• Check the circuit.

Checking the circuit

• Look at all the items on the circuit to ensure that they are working properly. Check for signs of appliance breakdowns or damage to lights and fittings. Do not plug in anything you suspect may be damaged, as the fuse will blow again. If you have home emergency cover, you can contact 24|7 Home Rescue to repair or replace the broken appliance.

• Ensure you are not overloading any sockets, such as by overloading extension cords.

• If you are unsure which appliance has broken, you may have to sacrifice a fuse to find out. Turn on your items individually until the fuse blows again. The item you switched on immediately before the fuse blew is the source of the problem.

• For further information, see ‘My fuse box keeps tripping – help!‘

Still having trouble?

Don’t attempt to make any changes to your electrical system if you are unsure or not confident. Some electrical work in the home requires compliance with Part P building control and needs to be done in accordance with BS 7671 wiring regulations. Don’t forget: electricity is very dangerous and can kill you.

Instead, contact 24|7 Home Rescue at 0345-3192-247 and we will assist you. Our technical teams will run through some very simple troubleshooting with you over the phone to see if your problem can be resolved easily, and if not, they will book one of our qualified and highly knowledgeable Part P certified engineers to get you back up and running as soon as possible.