Why is my electrical cable getting hot inside the wall when the cooker is on?
Quick answer
A cable getting hot inside the wall when your cooker is on almost always means the cable is undersized for the load, has a loose or corroded connection, or is buried under insulation that traps heat. Turn off the cooker at the isolator switch immediately and do not use it again until a registered electrician has inspected the circuit. Overheating cables are a serious fire risk and are not a problem you should leave or investigate yourself inside the wall.
🏠Homeowner view
If you have noticed warmth on the wall surface near your cooker circuit, or had an electrician mention the cable feels hot when your cooker is running, this is something you need to take seriously straight away. A cable that gets too hot is one of the leading causes of electrical fires in UK homes, and cooker circuits are especially vulnerable because they carry some of the highest loads in your house.
Here is what is most likely causing it, explained in plain language.
The cable is too small for the job. Cookers typically need a 6mm or 10mm twin and earth cable, and an older property might still have a smaller cable installed decades ago when cookers were less powerful. A cable that is too thin for the current passing through it heats up, just like a thin wire in an electric heater glows red.
There is a loose or bad connection somewhere. Loose connections at the cooker connection unit, the consumer unit, or any junction in the circuit create resistance. Resistance creates heat. Over time this can char plastic, melt insulation, and start a fire behind your walls.
The cable is buried under loft or wall insulation. If your home has been retrofitted with insulation, the cable may no longer be able to shed its heat into the surrounding air. This is a very common problem in homes that have had cavity wall or loft insulation added.
The circuit breaker or fuse is the wrong rating. If someone has fitted an oversized fuse or breaker, the cable can overheat before the protection trips.
What you should do right now.
1. Switch off the cooker at the cooker isolator switch on the wall.
2. Do not use the cooker again until the circuit has been checked.
3. Do not open sockets, remove faceplates, or probe inside the wall yourself.
4. Call a Part P registered electrician, ideally one registered with NICEIC, NAPIT, or a similar scheme.
An electrician will carry out a series of electrical tests on the circuit to find the exact fault. This is not a job you can safely diagnose or fix yourself, and under Part P of the Building Regulations, any remedial work on a cooker circuit must be notified to your local authority or carried out by a registered competent person.