Swap a socket for a USB socket

Replace an existing socket with a USB socket safely, checking wiring, box depth and wall type before fixing the new faceplate.

AB-01Turn off the power and lay out your kitSwitch off the correct circuit at the consumer unit and remove the fuse, or lock off the MCB if it has a lock-off facility. Prove the circuit is dead at the socket with your voltage tester before touching any wiring. Lay a dust sheet under the socket and set out your new USB socket, screwdrivers and a torch.

RULES

1 each · USB double socket (white)

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1 each · Two-pole voltage tester

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1 each · Insulated screwdriver set

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1 each · Dust sheet

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KNOW THE RULES

Swapping a socket for a USB socket on a like-for-like basis is not notifiable work under Part P — it's not a new circuit and this isn't a bathroom special location. You only need to notify building control for new circuits or work in a bathroom's zoned areas.

AB-02Remove the old faceplate and check the wiringUndo the two fixing screws holding the old faceplate to the box and pull it gently forward. Take a photo of the wiring before disconnecting anything, so you have a reference for reconnecting. Loosen each terminal screw and free the cables, keeping the earth, neutral and live wires separate and clearly identified.

AB-03Check the depth of your existing boxA USB socket has a charging module built in, so it needs a box at least 25mm to 35mm deep — older 16mm shallow boxes, common in older flats, are usually too shallow. Measure your existing box with a tape measure. If it's deep enough, keep it and skip ahead to wiring; if it's too shallow, you'll need to fit a deeper one first.

1 each · Tape measure

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AB-04Fit a deeper box if you need one — the fixing depends on your wallBefore drilling anywhere, sweep the area with a cable and pipe detector, then still treat the wall as live until you've proven otherwise; find your stopcock and check it turns, and keep the circuit isolated at the consumer unit before you cut into anything. In solid brick or block, drill a 6mm hole with a masonry bit and use a wall plug for the box's fixing lugs. In a timber stud — found by tapping for a solid sound, following a line of screw heads, or drilling a small pilot hole that brings out wood dust — screw the box lugs straight into the timber with 32mm wood screws. In a metal stud, spotted by a hollow sound and a pilot hole bringing out fine steel swarf, use self-drilling metal-stud fixings or plasterboard toggles, never plain wall plugs or ordinary wood screws, which strip straight through 0.5mm steel; a USB socket is light enough for these fixings alone. For dot-and-dab or lath and plaster, use a dry-lining ('bendy') box that grips the plasterboard skin with its own wing dowels rather than screwing into the masonry or laths behind.

1 each · Cable and pipe detector

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1 each · Deep dry-lining box (35mm)

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1 each · Deep masonry back box (35mm)

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1 pack · Self-drilling metal-stud fixings (pack of 10)

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1 pack · Wall plugs (pack)

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1 pack · 32mm wood screws (pack)

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1 each · 6mm masonry drill bit

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AB-05Wire in the new USB socketFollow the manufacturer's wiring diagram supplied with the socket — most USB sockets share the same live and neutral terminals as an ordinary socket, with the earth going to its own terminal or a short fly lead. Strip back only enough insulation to sit fully in each terminal, then tighten every screw firmly, as a loose terminal is the most common cause of a socket running warm. Fold any spare cable neatly into the box so nothing gets trapped behind the faceplate.

1 each · Wire strippers

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1 each · Terminal (electrician's) screwdriver

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AB-06Fix the faceplate and test itPush the new faceplate onto the box, tucking in the cables as you go, then fit the two fixing screws without overtightening — a cracked faceplate can't be repaired. Turn the power back on at the consumer unit and check the socket with a lamp, then check both USB ports actually charge a phone. If anything doesn't work, switch off again and recheck your terminal connections before retesting.

1 each · Small spirit level

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AB-07Tidy upSweep up any dust or off-cuts, especially if you cut a bigger hole for a deeper box, and vacuum around the socket. Dispose of the old socket and shallow box responsibly — most councils accept small electrical items at recycling centres. Keep your wiring photo and any spare fixings somewhere safe in case you need them again.

KNOW THE RULES

Before you start: Which electrical jobs can I do myself? Part P explained

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