How to Install a USB Socket UK: Depth, Ports & Wiring

A USB socket replaces a standard 13A socket and adds always-ready charging without adaptors — the single most requested upgrade in guest rooms and home refurbs. Installation is a like-for-like swap with two extra checks: back box depth and port type.

Safety first: Isolate the circuit at the consumer unit and prove dead with a voltage tester before removing the old socket. Like-for-like replacement is generally non-notifiable in England and Wales but must comply with BS 7671. If unsure, use a qualified electrician.

Check 1: back box depth

Wall facePlateUSBmodule35mm recommended (25mm min)The charging module takesthe space of an extra cable —measure your box depthbefore ordering.
Measure from wall face to box base. Full sizing table in the back box guide.

USB charging electronics sit behind the plate, so most USB sockets need a 25mm minimum box — 35mm is comfortable. Shallow 16mm boxes won't work.

Check 2: USB-A, USB-C or both

USB-C is now the standard for phones, tablets, and EU-mandated devices, and delivers faster charging (up to 30W+ on some plates). USB-A still suits older cables and devices. Mixed A+C plates cover everything — our USB-A vs USB-C guide compares options across our USB socket range.

Installation steps

  1. Isolate the socket circuit and confirm dead with a plug-in tester or lamp.
  2. Remove the old faceplate, test terminals, and photograph the wiring.
  3. Disconnect the conductors — typically two cables on a ring final; keep pairs together.
  4. Connect the new plate: brown/red to L, blue/black to N, sleeved earth to E. Metal plates: connect the plate earth terminal too. (Terminal diagram in our socket replacement guide.)
  5. Fold cables carefully — the USB module leaves less room; avoid crushing conductors against it.
  6. Refit, restore power and test both the 13A outlets and USB ports.

Specifying for hotels and rentals

FAQs

Can I fit a USB socket where my normal socket is?

Yes — it wires exactly like a standard 13A socket. The only extra requirements are a deep enough back box (25mm+) and careful cable folding.

How many amps do USB sockets charge at?

Typical plates deliver 2.4A–3.1A shared across USB-A ports; USB-C PD plates deliver 18–45W depending on model — enough for fast-charging phones and tablets.

Are USB sockets safe to leave on?

Yes. Quality UK plates are BS 1363 compliant, and the charging circuitry idles at negligible power when nothing is connected.