What is this?
Extension leads are a temporary solution for providing additional sockets, but they are one of the most common causes of electrical fires in UK homes. An extension lead getting hot indicates it is being overloaded, has a poor connection, or is of insufficient quality for the load being placed on it. The cable, plug, or socket block may overheat, and a coiled cable generates even more heat due to the inductive effect.
Common causes
- Overloaded extension lead — total appliance load exceeds the lead's rating
- Cable still coiled on the reel while under load (significantly reduces safe current rating)
- Cheap or non-compliant extension lead with undersized cable
- Daisy-chaining multiple extension leads together
- Loose connection inside the extension block or plug
- Running high-draw appliances (heaters, kettles) from an extension lead
Is it dangerous?
Yes, very. Extension lead fires are one of the top causes of accidental domestic fires in the UK. A hot extension lead means it is being overloaded or has a fault. Coiled extension reels are particularly dangerous — a cable rated for 13A when fully unwound may only safely carry 5A when coiled. Never run heaters, kettles, or other high-draw appliances from an extension lead unless it is fully unwound and appropriately rated.
Can I fix it myself?
Stop using the extension lead immediately and let it cool. Check the total wattage of everything plugged into it — this must not exceed the lead's rating (usually 13A / 3,120W). Always fully unwind reel-type extension leads before use. Do not daisy-chain extension leads. If the lead is damaged, discoloured, or the plug is melted, discard it. Consider having additional permanent sockets installed instead.
When to call an electrician
Call an electrician if you regularly need more sockets than you have — they can install additional permanent socket outlets safely. If the extension lead has caused any damage to the wall socket, that socket needs inspecting. If an extension lead has melted or caused a fire, the socket it was plugged into must be checked.
What will an electrician do?
Inspect the wall socket the extension lead was plugged into for damage
Advise on the appropriate permanent socket installation for your needs
Install additional double socket outlets where needed
Check the circuit capacity to ensure it can handle the additional load
Issue a Minor Works Certificate for any new sockets installed
Typical cost
£80 – £200
Per additional double socket installed. Costs depend on the distance from existing wiring and the finish required (surface-mounted vs flush). Having several sockets added in one visit is more cost-effective.
