Inspired by a helpful YouTube guide. We based this walk-through on the popular UK guide “How to fit a USB Plug Socket in the UK - Old and New Wiring Colours”, which covers both the old red-and-black wiring and the newer brown-and-blue colours you will find in properties wired after 2006. If you are unsure which yours is, this will sort it out quickly.
1. Turn off the power at the consumer unit
Find the circuit breaker for the ring main covering the socket you are working on - usually labelled “Sockets” or “Ring Final”. Switch it off, then test the socket with a plug-in tester or a lamp to confirm there is no power.
Do not rely on switching off at the socket alone. Always isolate at the board. Tape over the breaker or leave a note so nobody flicks it back on while you are working.
2. Remove the old faceplate
Undo the two screws on the faceplate and carefully pull the socket away from the back box. The cables will still be connected, so do not yank - ease it out and let it hang.
Take a photo of the existing wiring before you touch anything. Old wiring (red, black, bare earth) and new wiring (brown, blue, green-and-yellow) both follow the same terminal layout on the faceplate, but the colours differ. The photo gives you a reference if you lose track.
3. Identify the wire colours
In new-colour wiring: brown is Live, blue is Neutral, green-and-yellow is Earth. In old-colour wiring: red is Live, black is Neutral, bare copper or green is Earth.
If you find both old and new colours in the same back box, the circuit has been extended at some point. That is fine - just connect each like-for-like: Ls together, Ns together, Es together.
4. Disconnect the wires from the old socket
Loosen the terminal screws and pull each wire free. On a ring main socket there may be two cables - one in, one out - giving you two wires in each terminal. Note which terminal each wire came from before you remove them.
Give each wire a gentle tug to check the copper is secure and not corroded. If you see green verdigris or the wire looks brittle, this job needs a qualified electrician.
5. Connect the wires to the new USB socket
USB sockets have the same three terminals as a standard socket: L, N, and E (or marked with arrows or symbols). Connect Live to L, Neutral to N, Earth to E. Tighten each screw firmly so the wire cannot be pulled free with a firm tug.
The USB circuit is self-contained within the faceplate - you do not need to wire it separately. The USB ports just take power from the socket terminals automatically.
6. Fold the cables and fit the faceplate
Ease the cables back into the back box in a loose figure-of-eight fold - do not force them in a straight bundle as this can strain the terminals. Offer the faceplate up to the box and start both screws by hand before tightening either one fully.
Check it sits flush. If it is tilting, one cable is probably sitting across the back and pushing it forward. Have another go at folding.
7. Restore power and test
Switch the circuit breaker back on. Plug in a lamp or tester. Try both the standard socket positions and check a phone charges from the USB ports. If the RCD trips immediately, switch off and recheck the connections - a loose or wrongly placed wire is the most common cause.
A plug-in socket tester (about £8 from any DIY shop) will confirm correct polarity in under ten seconds. Worth having one in the drawer.
When to call a handyman
This is a straightforward like-for-like socket swap - it counts as minor electrical work under Part P and does not require notification to Building Control. However, if you open the back box and find scorching, damaged insulation, aluminium wiring, or anything that looks wrong, stop and call Richard. Dodgy wiring needs assessing before anything else goes in.
Need electrical work done safely?
The Sandwich Handyman can fit USB sockets, replace faceplates, and carry out minor electrical work in Sandwich and East Kent. We can also advise when a job needs a fully qualified electrician.
Contact Richard