Burning smell from a plug socket: what to do now

What to do in the next five minutes

1. If there is smoke, flame or crackling, get everyone out and call 999. Do not try to put out an electrical fire with water.
2. If the socket is hot or scorched, do not touch the plug. Switch off at the main switch on your consumer unit if you can reach it safely.
3. If the socket looks normal and is not hot, switch it off at the socket and unplug the appliance.
4. Check the plug without opening it. Look for brown marks, melting or a bent pin.
5. Leave the socket off and do not plug anything else into it.
6. Smell the other sockets and the consumer unit. If the smell is coming from the board, switch off at the main switch and see our guide to a burning smell from the fuse box.

Do not take the socket off the wall to look. The terminals behind it are live unless the circuit has been isolated and proved dead with a tester.

What causes it

Electricity heats any connection that is not tight. A screw terminal that has worked loose, a cable that was not pushed fully into a terminal, or a plug pin that does not grip properly all create resistance. Resistance makes heat. Over time the heat browns the plastic, and the plastic gives off the smell.

What you notice	Most likely cause
Smell only when a heater or dryer is on	Heavy load through a weak connection
Brown marks on one outlet of a double socket	Loose terminal or worn contacts on that side
Plug pins discoloured or plug warm	Loose plug terminal, wrong fuse, or worn socket contacts
Smell from an extension lead	Lead overloaded or damaged
Smell with no appliance plugged in	Loose connection on a cable passing through the socket box
Smell at several sockets on one circuit	Fault on the ring circuit itself

A ring circuit is the usual way sockets are wired in UK homes. The cable runs from the consumer unit round each socket and back again. A loose joint anywhere on that loop can make one socket run hot.

The winter pattern

Overheating sockets are much more common when it is cold. People plug in electric heaters, oil filled radiators and tumble dryers, often into the same double socket or an extension lead. Those appliances draw a lot of current for hours. A connection that coped with a lamp and a phone charger all summer starts to cook.

The London Fire Brigade lists hot plugs and sockets among the warning signs of loose or dangerous wiring, alongside scorch marks and flickering lights. It also says it has attended 26,376 electrical fires in London since 2017.

Simple rules:

• Plug heaters straight into a wall socket, not an extension lead.
• One high power appliance per double socket.
• Do not run a heater and a tumble dryer from the same socket.
• Uncoil extension reels fully if you must use one.

Sutton homes and older sockets

Sutton has a large share of interwar houses. The VOA stock of properties for 2025 shows 40.6% of homes there were built between 1919 and 1939, with semis and terraces in Cheam, Carshalton, Wallington and the St Helier estate making up much of that.

In houses of that age, sockets have usually been replaced once or twice. Common findings in this kind of housing:

• sockets added on spurs from an original socket, all sharing one connection
• sockets in kitchen extensions run from the nearest available point
• worn socket fronts that no longer grip plug pins firmly
• older cable behind newer sockets, where only the faceplate was changed

If you rent, the London Fire Brigade notes you can ask your landlord to have the electrics checked by a qualified electrician. See our Sutton electrician page for more on local housing.

What the electrician does

When we attend for a burning smell, the job is to make it safe first and then fix the cause.

1. Isolate and prove dead. The circuit is switched off and tested to confirm it is safe to work on.
2. Inspect. The socket comes off. We look at the terminals, the cable ends and the back box for heat damage.
3. Test the circuit. We check the ring is complete and the connections are sound, and that the earth is in place.
4. Repair. Usually that means cutting back damaged cable, remaking the connections and fitting a new socket. If the cable is heat damaged further back, more work is needed.
5. Check the rest. If one socket has overheated, others on the same circuit may be close behind. We test before leaving.

Read more on our burning smell, sparking or hot sockets page. If the socket also sparked, our post on a plug socket that sparked explains the difference between a normal tiny spark and a dangerous one.

Cost

There is no fixed price because the damage decides the job. A single socket change is small. A heat damaged cable inside a wall is not. We look first and the price is confirmed after a look at the job, before any repair starts.