How To Change A Plug Socket
A step-by-step photo guide to swapping a tired socket for a new double or USB socket safely.
The short answer
To change a plug socket, switch off the circuit at the consumer unit and prove the socket is dead with a tester. Unscrew the faceplate, note which wire goes where and loosen the terminals. Connect brown to live, blue to neutral and green and yellow to earth on the new socket, then screw it back and test it with the power on.
A cracked, yellowed or loose socket front lets a room down, and swapping it for a new one is one of the more satisfying small jobs in a house. The photo under the title shows the difference, with a tired white socket that has a crack running down it next to the polished chrome replacement we fitted.
Plenty of people change sockets to add USB charging, too. USB wall sockets fit the same back box as a standard double, so you get charging ports without losing an outlet or hunting for adapters.
Safety Before You Start
You need to know where your consumer unit is and which breaker feeds the socket you're working on. If the labels are missing or worn, turn off the whole board instead.
A plug-in socket tester gets used twice on this job, first to show the socket has gone dead and again to check the wiring once the new one is on. It only reads the socket through its pins, though. For a firmer answer before you touch any wires, put a two-pole voltage tester across the terminals once the front is off.
In England and Wales, swapping a socket like for like isn't notifiable under the Building Regulations. New circuits, a new consumer unit and most electrical work in bathrooms are, and those belong with a registered electrician. If anything behind the faceplate looks scorched, brittle or different from what we show below, stop and call one in.
The step-by-step guide below has a photo at each stage from a socket we changed ourselves.
How To Change A Plug Socket
1. Isolate The Circuit
Plug a socket tester into the socket and switch it on so it lights up or beeps, which tells you the socket is live. Then turn off the circuit at the consumer unit and watch the tester go quiet. If it carries on, you've switched off the wrong breaker, so put it back on and try the next one.
Once the right circuit is off, stick a piece of tape over the breaker so nobody switches it back on while you work.
2. Unscrew The Old Faceplate
Take out the two screws at either end of the faceplate and ease it away from the wall to reveal the wiring. Keep the screws, as the new socket's screws won't always match the threads in an older back box.
3. Loosen The Terminal Screws
With the faceplate pulled forward, the terminal screws are on the back. Before you undo anything, take a photo of which wire goes where. Then loosen each terminal and pull the wires out.
4. Prepare The Wires
Check the ends of the wires for damage. If any are frayed, nicked or blackened, trim them back and strip the insulation to leave at least 5mm of clean copper. Any bare earth wire needs a green and yellow sleeve over it before it goes into the new socket.
5. Wire The New Socket
Open up the terminals on the new socket and find the markings for live (L), neutral (N) and earth (E). Brown wires go into the live terminal, blue into neutral and green and yellow into earth. Older wiring uses red for live and black for neutral, and they go into the same terminals.
On a ring circuit, like the one in our photos, there are two wires of each colour and both go into the same terminal.
6. Tighten The Terminals
Tighten every terminal screw firmly, then give each wire a gentle tug to check it's held. No bare copper should be showing outside the terminals, so trim and refit any wire that sticks out.
7. Refit The Faceplate
Fold the wires neatly into the back box without trapping them, push the socket into place and refit the two screws. Hold a small spirit level along the top edge and adjust before you tighten them fully, as a squint socket is easy to spot from across a room.
8. Turn The Power Back On
Take the tape off the breaker and switch the circuit back on at the consumer unit. If the socket needs adjusting after this, switch the circuit off again first.
9. Test The New Socket
Plug in your socket tester and check that every light shows the wiring is correct. The tester also flags a missing earth or swapped live and neutral, which is why this step matters. Our short video shows how quickly the check is done:
When Was The Last Time You Tested Your Plug Sockets? A Tester Is Required & We've Tested Lots!
How To Change A Single Plug Socket To A Double
Swapping a single socket for a double takes more work, because the back box has to get bigger. A surface-mounted double box is the quickest route. We're covering the hardest version here, a flush double socket in a solid wall.
1. Isolate The Circuit And Remove The Single Socket
Turn the circuit off at the consumer unit, confirm the socket is dead with your tester, then take off the faceplate and disconnect the wires as in steps 2 to 4 above.
2. Mark Out The Double Back Box
Hold a double back box over the old single box, level it and draw round it in pencil. That outline is your guide for how much wall to chop out.
3. Chop Out The Wall
We prefer an SDS hammer drill for cutting out the extra space, as the photo shows. A bolster and club hammer does the same job by hand, with a row of holes drilled around the outline first so the plaster breaks cleanly. Keep the old cables out of the way as you go.
4. Clear The Debris
Vacuum out the dust and loose bits so the back box sits flat. Test fit it, and if it won't sit flush with the plaster, chop out a little more until it does.
5. Fix The Back Box
Knock out the cable entry, fit a grommet so the box edges can't rub through the insulation and feed the cables through. Mark, drill and plug the fixing holes, then screw the box firmly to the wall.
6. Wire And Fit The Double Socket
Connect the wires and fix the new faceplate following steps 4 to 7 in the guide above. The cables in our photo are the older red and black colours, so red goes to live and black to neutral.
7. Test The Double Socket
Switch the circuit back on and run the socket tester across both outlets. Once every light confirms the wiring is right, the conversion is done.
8. Make Good Around The Socket
Chopping out by hand or with a drill always leaves a ragged edge. We filled around the socket with a fine decorator's filler for small gaps, sanded it smooth once dry and painted over it with the same emulsion used on the walls. Run low-tack masking tape around the faceplate first so filler and paint stay off the new socket.
Changing A Socket Yourself
Changing a plug socket is well within reach of a careful DIYer. The rules that matter are simple enough. Isolate and test the circuit before you start, test again when you finish and photograph the wiring before you disconnect anything. If what you find behind the faceplate doesn't look like our photos, that's the point to call an electrician.
Other Questions We Get Asked
Can I change a plug socket myself?
Yes, you can change a plug socket yourself in England and Wales, as replacing a socket like for like isn't notifiable building work. You must isolate the circuit and prove it's dead before touching any wires. Adding a new circuit, replacing the consumer unit or doing most electrical work in a bathroom needs a registered electrician or a building control notification.
Which wire goes where in a UK plug socket?
In a UK plug socket, the brown wire goes to the live terminal marked L, the blue wire to neutral marked N and the green and yellow wire to earth marked E. In older wiring, red is live and black is neutral. On a ring circuit there are two wires of each colour, and both go into the same terminal.
Do I need to turn off the main switch to change a socket?
You only need to turn off the breaker that feeds the socket, but the main switch is the safest choice if the consumer unit isn't labelled. Either way, check the socket is dead with a tester before you start. Tape over the switched-off breaker so nobody turns the power back on while you're working.
Can I replace a normal socket with a USB socket?
Yes, a USB socket replaces a standard socket using the same wiring and steps. Check the depth of the existing back box before buying, because USB sockets have electronics behind the faceplate and some need a deeper box. If yours is shallow, fit a deeper back box or pick a USB socket made for standard mounting depths.
Why test the socket both before and after the job?
The first test proves you've cut the power to the right socket, so you're not working on a live circuit. The second confirms the new socket is wired correctly, and a plug-in tester will flag a missing earth or swapped live and neutral. Before touching wires, a two-pole voltage tester across the terminals gives a firmer answer than the plug-in tester alone.
What if the wires in my back box are red and black?
Red and black are the old colours for live and neutral, and they connect just like brown and blue. Red goes to L and black to N. Our single to double conversion had this older cable, and it wired up the same way. If the earth is bare copper, slip a green and yellow sleeve over it first.
What's the hardest part of swapping a single socket for a double?
Chopping out the wall for the bigger back box is the hard graft. We used an SDS hammer drill, though a bolster and club hammer will do it by hand if you drill a row of holes around the outline first. If you'd rather not chop into the wall at all, a surface-mounted double box is the quickest way round it.
Why take a photo before disconnecting the wires?
Once the old socket is off, it's easy to forget which wire came from which terminal, and a quick photo settles it. Hang on to the old faceplate screws while you're at it, since new ones don't always match the threads in an older back box.
Richard has spent years renovating properties and turning them into rentals and Airbnbs. Like a lot of people he started out as a beginner, and these days there isn't much DIY he won't take on.