Plug Socket Not Working? How to Find the Fault Safely

If a plug socket has stopped working, start by finding out how much has gone dead. Test the socket with something you know works, like a phone charger or a lamp, then try the other sockets in the room. One dead socket usually means a fault at that socket. A whole room or group of sockets dead at once points to a tripped breaker or RCD at the consumer unit, or a break in the circuit somewhere upstream.

We get this call most weeks. Kettle fine yesterday, stone dead today, and the worry is always the same: is this a small job, or is something burning behind the wall? Most of the time it is neither dramatic nor expensive. But the pattern tells you a lot before anyone picks up a screwdriver, so here is how we read it.

First, the checks that cost nothing

Before assuming the socket has failed, rule out the boring causes.

• Test with a known working appliance. Bring a lamp or charger from another room. If it works in the "dead" socket, the problem was your appliance all along.
• Check the fuse in the plug. UK plugs hold a small cartridge fuse, usually 3A for lamps and electronics and 13A for kettles, washing machines and similar. Electrical Safety First's advice is to replace a blown fuse only with one of the same rating. Never go up a size to stop it blowing.
• Check the socket's own switch. A switched socket with a worn rocker can sit half-on. If the socket is fed from a fused spur nearby, that spur has its own fuse worth checking too.
• Check anything in between. Extension leads, smart plugs and timers all have their own fuses or cut-outs. A tripped extension lead looks exactly like a dead socket.

Check the consumer unit

If more than one socket has gone, or a whole room has no power to the sockets, go to the consumer unit. Look for an MCB (the small breakers for individual circuits) that has dropped to the middle or off position, or an RCD that has tripped. Sockets and lights are on separate circuits, so dead sockets with the lights still on is completely normal and points here first.

Reset it once. Push the switch fully off, then back on. If it holds, carry on and keep an eye on it. If it trips again straight away, unplug everything on that circuit and reset. Then plug things back in one at a time. The appliance that makes it trip is your faulty item, and a kettle or iron leaking to earth is a very common culprit.

If it trips with nothing plugged in at all, the fault is in the wiring itself, and that is where DIY stops. Our guide on how to reset a tripped fuse box walks through the reset safely, and why a fuse box keeps tripping explains what the repeat pattern means.

When it is just the one socket

Everything else on the circuit works, one socket does nothing. That narrows it down to the socket itself or its immediate wiring:

• A loose terminal behind the faceplate. Screws relax over years of plugs going in and out, especially on sockets that get daily use. The connection heats, then lets go entirely.
• A failed internal switch. The rocker wears out and stops making contact even though it clicks.
• Worn contacts. The metal grips inside no longer bite on the plug pins. You often get a hint of this first, a plug that feels loose or falls half out.
• Damage in the back box. A crushed cable or a box that has pulled away from the wall, taking the connections with it.

The clue is usually the history. A socket that has been stiff, crackly or loose for months before it died is telling you what happened.

One thing to hold onto: a dead socket can still be live. The break can be in the switched live or the neutral while other terminals inside sit at mains voltage. NICEIC's own warning on a faulty socket is blunt: do not touch it, because if the breaker has not tripped it may still be connected to live electricity.

Double socket with only one side working

This one surprises people, but it has a tidy explanation. Both halves of a double socket share the same terminals behind the faceplate, so a loose wire would kill both sides together. One side dead and the other fine almost always means the socket accessory itself has failed on one side: burnt contacts from years of a heavy load like a tumble dryer, or a jammed safety shutter, the little flap inside the holes, stopping the plug seating properly.

The fix is a like-for-like replacement socket. It is a small job, but it still means working dead and testing afterwards, so treat it like any other electrical repair rather than a five minute fiddle.

Sockets not working in one room

Most UK socket circuits are rings: the cable leaves the consumer unit, loops through each socket in turn, and returns. Some rooms, especially extensions and kitchens added later, sit on a spur or a radial leg off that ring. Either way, the sockets are daisy-chained, and that has a consequence most people never think about.

A fault at one socket does not stay at that socket. If a connection burns through at socket number two in the chain, sockets three, four and five lose their feed while socket one carries on working perfectly. So the homeowner finds the front bedroom fine and the back bedroom dead, or half the kitchen out, and assumes three separate faults. It is one fault, upstream.

This is the "it worked yesterday" chain, and honestly it is the fault we find most often. A terminal that has been loose for months heats up every time the kettle or the hoover runs. It arcs a little, carbon builds, the connection gets worse, and one day it burns through completely. Everything downstream goes dead overnight, with no bang, no trip, nothing at the consumer unit. Finding it means testing along the circuit until the voltage disappears, which is exactly what our fault finding and repairs work involves.

Sockets that work intermittently

A socket that works sometimes, dies when you wiggle the plug, or cuts out when a heavy load runs is the loose connection caught early. It makes and breaks as the metal heats and cools. The faceplate can feel warm, and there may be a faint crackle if you listen close.

Do not leave this one. Every arc damages the contact a bit more, and intermittent faults are how scorched back boxes start. It will not heal itself, and it will not get cheaper to fix by waiting.

Scorch marks, crackling or sparks from a plug socket

Stop using the socket. Switch it off at the rocker if you can do that without touching anything damaged, then turn the circuit off at the consumer unit and leave it off.

The warning signs NICEIC tells homeowners to act on are a burning or fishy smell, a socket that is loose, hot or discoloured, and crackling or buzzing when you plug something in. Electrical Safety First says the same about arcing sounds, burn marks and fuses blowing repeatedly: do not ignore them. A tiny snap as a plug goes in can be normal inrush current. Repeated crackling, visible arcing or any smell of burning is not.

If you have caught a hot, fishy smell near a socket, our post on burning smell from a socket covers what is usually causing it and what to do right away.

Why a broken ring is dangerous even when everything works

Here is the one that catches people out, because there is no symptom at all. If one leg of a ring circuit breaks or comes disconnected, every socket on it keeps working. The whole ring simply gets fed down a single cable instead of two.

The problem is capacity. A ring on a 32A breaker relies on the load being shared by both legs of 2.5mm cable. Feed everything down one leg and that cable can be asked to carry more than it should, all day, with the breaker seeing nothing wrong. No trip, no dead socket, no warning. It only shows up on a ring continuity test, the kind done during an EICR or proper fault finding. This is why "everything works" does not always mean "everything is fine".

What you can safely do, and where to stop

Sensible to do yourself:

• Test the socket with a lamp or charger you know works.
• Check and replace the fuse in a plug, like-for-like.
• Reset a tripped breaker or RCD once, and unplug appliances to hunt a tripping fault.
• Note the pattern: which sockets, which rooms, what was running when it went.

Where to stop: the faceplate. Behind it are live terminals, even on a socket that appears dead. Swapping a socket like-for-like is not normally notifiable work under Part P, the building regulation covering electrical safety in dwellings, but it still has to be done with the circuit isolated, proved dead, and tested afterwards. If you are not set up to do that, that is the line, and there is no shame in it. We prove dead every single time, on jobs we have done a thousand times, because the one time you skip it is the one that bites.

When a socket does need replacing, or you want extra outlets added properly, our sockets and switches service covers it.

Frequently asked questions

Why did my plug socket suddenly stop working?

Most often a tripped breaker or RCD at the consumer unit, or a loose connection somewhere on the circuit that finally burned through. Check the consumer unit first, then test other sockets to see how wide the fault is.

Why is only one side of my double socket working?

The socket itself has failed on one side, usually burnt contacts or a jammed safety shutter. Both halves share the same wiring, so a wiring fault behind the faceplate would kill both together. The fix is a replacement socket.

Can a socket be dead but still live?

Yes. The break can be in one conductor while other terminals inside remain at mains voltage. Never open or touch a suspect socket without isolating the circuit at the consumer unit and proving it dead first.

Why are the sockets in one room not working but the lights are?

Sockets and lights run on separate circuits, so one can fail while the other is fine. A tripped MCB or RCD, or a break at one socket on the circuit, takes out a group of sockets while the lights carry on as normal.

Is it safe to keep using a socket that sparks?

A brief snap as a plug goes in can be normal. Repeated crackling, visible arcing, heat or any burning smell is not. Stop using the socket, switch the circuit off at the consumer unit, and get it looked at before it gets worse.

How much does it cost to fix a dead socket?

As a rough UK market guide, replacing a single socket sits at the low end of an electrician's minimum charge, while tracing a break in a circuit takes diagnostic time that varies with how hidden the fault is. Costs vary, so always get a fixed quote agreed before work starts.

No power to sockets and not sure where the break is? We test the circuit properly and find the actual fault, not the symptom. See our fault finding and repairs service or call us on 020 3653 2600 for a straight answer and a fixed quote.