Try to fit a normal double socket in a bathroom and BS 7671 stops you before you've finished tightening the screws.

Why Can't You Just Fit a Normal Socket in a Bathroom?

BS 7671 Section 701 treats any room with a bath or shower as a special location, splitting it into Zone 0 (inside the bath or shower tray itself), Zone 1 (directly above, up to 2.25m), and Zone 2 (0.6m beyond that). Regulation 701.512.3 rules out standard socket outlets in all three zones, and even outside them a normal socket has to sit at least 2.5m horizontally from the Zone 1 boundary. In most UK bathrooms, that rules out a standard socket almost anywhere in the room.

Shaver sockets get a specific exemption. A unit built to BS EN 61558-2-5 has an isolating transformer inside it, which means the output is not classed as a mains socket outlet in the way BS 7671 defines the term. That is why every hotel bathroom you have ever charged a toothbrush in has a shaver socket rather than a plug socket, and why fitting a normal double socket in a bathroom is not a grey area, it is simply not permitted.

Where Exactly Can You Fit One?

In practice, that means a shaver socket mounted beside a bathroom mirror, which usually sits in Zone 2, is exactly where the regulations expect it. Trying to squeeze one into Zone 1 directly above a bath, on the other hand, is not allowed regardless of the transformer inside it.

Nexus Metal vs Evolve: Does Back Box Depth Matter?

BG's Nexus Metal shaver sockets need a 47mm minimum back box depth to house the transformer, which is deeper than most standard sockets and worth checking before you commit to a retrofit into an existing box. The screwless Evolve range uses a shallower profile and fits a standard depth box in most cases, which makes it the easier retrofit option if you are replacing rather than fitting into a new stud wall.

Both ranges perform identically as shaver sockets, so the choice comes down to back box depth and finish rather than function. The Nexus Metal range sits within the wider British General collection if you're matching the rest of a bathroom to the same finish family, and the screwless option pairs with BG Evolve Black Chrome or any of the other Evolve finishes.

The Common Mistake: Using It for a Hairdryer

A shaver socket's isolating transformer is designed for low-current loads like shavers and electric toothbrushes, typically rated well under 200W. Plugging in a hairdryer, which commonly draws 1000-2200W, will trip or damage the unit, because it was never built to supply that kind of current. This is the single most common misuse of these sockets, and it is worth mentioning to anyone specifying a bathroom refit that a hairdryer needs a proper socket outside the zones, not a shaver socket pressed into service for something it was not designed to run.

Is Fitting One Notifiable Under Part P?

Because a bathroom counts as a special location, adding a shaver socket where none existed before is generally notifiable work under Part P, unlike a like-for-like replacement in an ordinary room. A straightforward swap of an existing shaver socket for a new one, without altering the circuit, typically falls outside that requirement, but new installation in a special location does not. If in doubt, use a registered electrician who can self-certify the work rather than notifying building control separately.

Frequently Asked Questions