Why is my electrical cable getting hot inside the wall when the tumble dryer runs?
Quick answer
A cable getting hot inside the wall when your tumble dryer runs almost always means the cable is undersized for the load, a connection is loose somewhere in the circuit, or the cable is buried under insulation with no room to shed heat. Stop using the dryer immediately. A hot cable is a fire risk. Do not ignore it or assume it will be fine. Call a registered electrician to inspect the circuit before using the appliance again.
🏠Homeowner view
If you have noticed that the wall feels warm near your tumble dryer socket, or that the cable itself feels hot to the touch where it enters the wall, this is a serious warning sign that something is wrong with the electrical circuit. Here is what is happening and what you should do.
Tumble dryers are high-demand appliances. A typical electric dryer draws between 10 and 13 amps continuously, and heat pump models can still pull 6 to 10 amps. If the cable supplying the dryer is not rated to handle that current safely, it will overheat. Think of it like water through a hosepipe that is too narrow. The restriction creates pressure, and in electrical terms that pressure becomes heat.
The most common reasons a cable gets hot are these.
1. The cable is the wrong size for the circuit. A 2.5mm squared cable protected by a 32A breaker, for example, simply cannot carry that load safely in all installation conditions.
2. A loose or corroded connection at the socket, at the consumer unit, or at a junction somewhere in the wall is creating resistance. Resistance creates heat at that point and along the cable.
3. The cable is buried under loft insulation or clipped close to thermal insulation in a wall, which stops heat escaping. Even a correctly rated cable will overheat if it cannot dissipate heat.
4. The circuit is shared with other loads and the total current demand is too high.
What you can safely check yourself.
Check the socket face plate. If it feels warm or is discoloured, that is a sign of a connection problem inside.
Check the plug on the dryer. It should be cool. A hot plug top means a loose pin or a corroded contact.
Check the fuse in the plug is the correct rating. For most tumble dryers this should be a 13A fuse.
Check nothing heavy is sitting on or pinching the cable where it leaves the appliance.
What you must not do yourself.
Do not open the socket or the consumer unit. Do not try to rewire anything. Do not assume the circuit breaker will protect you. A breaker protects against short circuits, not against slow overheating of an undersized cable.
Stop using the dryer now and call a registered electrician, ideally one registered with NICEIC, NAPIT, or ELECSA. This is a genuine fire risk inside your walls.