Fixing a Blown Fuse in a Fuse Box! Step-by-step

There are a few different types of fuse boxes.

Approximately 12 – 18% of UK homes still have traditional fuse boxes (also known rewireable fuse boxes).

‘Fixing a blown fuse’ in one basically means rewiring/replacing it. 

Below is a step-by-step guide on how to do it.

Note: Fixing a fuse in a plug of an appliance is a different process.

How to know when a fuse has blown

You will know if a fuse has blown if:

• Your lights suddenly go out
• Your electrical appliance(/s) stops working.

It could be caused by:

• Too many appliances being plugged in at one time (i.e. overloading your circuits) 
• Faulty wiring of one of your devices
• A broader power cut in your street.

Important note: Know what kind of fuse box you have

There’s a difference between a more modern ‘fuse box’ (consumer unit) tripping and fuses in older fuse boxes blowing.

The former might only require a switch being flipped. The latter involves a fuse being fixed (/replaced), which is what this article is about. 

Please remember that electrics are dangerous. Although changing a fuse is a task you can do yourself at home, if you are not confident in your ability to do so or are concerned about faulty electrics, it’s always best to get in touch with a qualified electrician.

Changing a fuse in a traditional fuse box

Step 1: Get the right replacement fuse

If your traditional fuse box blows a fuse, you – or preferably, a hired professional – will need to replace that fuse.

Fuses in traditional fuse boxes are basically specific wires with a specific amperage rating. Today, they are much less widely available, even in hardware stores.

Different circuits in the fuse box require different amperages. For example: 

• Light circuits often require 5A/6A
• Socket (/ring) circuits often require 30A
• Large appliance (cookers, stoves) circuits often require 45A.

Note: These are common cases, but they don’t apply to all fuses. Always check the amperage on your fuse box circuits.

Using the wrong materials have consequences

When traditional fuse boxes were more common, some people replaced fuses with substitute materials, such as: 

• Foil
• Paperclips
• Nails
• Wire with the incorrect amperage.

This created serious risk, which sometimes had serious – even fatal – consequences. 

Step 2: Turn off all appliances

This includes your lights, your boiler and anything else you may have had running when the circuits cut.

Step 3: Find your fuse box

You’ll usually find an older fuse box in:

• Garages
• Utility rooms
• Hallways
• Cupboards under stairs.

They don’t have modern “flick-to-reset” switches. So, accessibility is even more critical.

Reaching it easily in the dark is even more important when you need to replace a blown wire rather than just flip a switch (like in newer consumer units).

It is vital to leave the area unobstructed. If the fuse box is high up, keep a sturdy stepladder nearby.

Step 4: Turn the main fuse box switch off 

Make sure you have dry hands and are standing on a dry surface

The fuse box should have a relatively large main switch. Rotate it to the OFF position (it will usually be clearly marked “ON” and “OFF”).

Note: You might hear a loud “clunk” and feel some resistance. This is normal for older heavy-duty spring-loaded switches.

Next, check that the power is actually dead by testing whether the lights work or not. You can also try a known working appliance (like a lamp) in a socket.

Even with the main switch off, the wires entering the box from the meter are still live. Never poke anything into the “busbars” or the main terminals behind the cover.

Step 5: Inspect fuse carriers

Inspect the fuse carriers to see which fuse has blown. You’ll be able to tell because it will be one of the following:

• Physically broken
• Burnt through
• Discoloured.

Step 6: Remove the blown fuse carrier

Use a screwdriver to loosen the carriers screws and remove the broken fuse wire. 

Having the right sized screwdriver stored next to the fuse box is ideal for occasions like this! 

Step 7: Insert new fuse wire

Thread the new fuse wire through the central part of the carrier and wrap it around the first screw in a clockwise motion and then the second screw.

Tighten the screws and remove any excess fuse wire with wire cutters

Step 8: Put carrier back inside fuse box

Place the carrier back inside your fuse box and turn on the master switch.

Your circuit should now be fully repaired and your electricity back on.

If your fuse blows again immediately…

If the fuse blows immediately after you plug one of your devices back in, one of two things are likely happening:

• The circuit is likely shorting
• You have a faulty appliance.

At this point, you should seek advice from an electrician.

Prefer to outsource home care issues?

Would you rather a professional handle your fuse box issues? 

Our home cover gives you peace of mind about the causes (and costs) involved.

Hometree offers home care plans you can trust, with quick and convenient call-outs and a 24/7 UK helpline. 

What’s more, we don’t put caps on claims!