Bathroom zones explained: what electrics can go where

Bathroom zones are the areas around a bath or shower where the wiring regulations limit which electrics can go and how well sealed they must be. Zone 0 is inside the bath or tray, zone 1 rises above it to 2.25 m, and zone 2 runs 0.6 m beyond that. We cover the measurements, the IP ratings, where fittings can go and when the work needs certifying.

What are bathroom zones?

Bathroom zones come from BS 7671, the wiring regulations electricians work to across the UK. They are measured from the bath or shower tray, not from the walls of the room, and Approved Document P describes the same space for England: up to 2.25 m above the floor and 0.6 m out from the edge of the bath or tray.

Zone 0

Zone 0 is the inside of the bath or shower tray. Fittings there must be rated at least IPX7, which survives temporary immersion, and run at 12 V or less, so in practice only sealed bath or tray lighting goes in.

Zone 1

Zone 1 is the space directly above the bath or tray, up to 2.25 m from the floor. Fittings need at least IPX4, and a mains-voltage fitting there also needs a 30 mA RCD. Shower lights and extractor fans are the usual zone 1 fittings.

Zone 2

Zone 2 is a band 0.6 m wide around zone 1, to the same height, and needs IPX4 as a minimum. Wall lights, illuminated mirrors, heated towel rails and shaver sockets commonly sit here.

Outside the zones

Anything beyond zone 2 is outside the zones, often called zone 3. No minimum IP rating applies there unless water jets are used for cleaning, and a ceiling light that is not directly above the bath or shower is usually out here.

Walk-in showers with no tray

A wet room or walk-in shower has no tray edge, so the zone is measured from the fixed shower head. In England the special location then runs 1.2 m out from the shower head, still to 2.25 m high, which in a small wet room takes in most of the floor.

IP ratings for bathroom zones

An IP rating is a two-digit code for how well a fitting keeps out solids and water. The first digit, 0 to 6, covers dust and solid objects. The second covers water, and a higher number keeps out more. An X means the fitting was not rated for that, so IPX4 and IP44 give the same water protection.

IP44 is the minimum for zones 1 and 2. Many shower lights are sold at IP65, which adds protection against jets and dust, and that is the rating we would buy for a light directly over the shower head.

What electrics can go where in a bathroom

The zone sets the rating a fitting needs. Whether fitting it needs certifying depends on the nation, and the right-hand column is England's rule.

In England the line falls at the edge of the zones. A new light point above the bath needs certifying, while the same point 1 m from the bath, on an existing circuit, does not. A like-for-like swap is never notifiable, but the new fitting still needs the right rating for its zone.

Can you have a plug socket in a bathroom?

Only where it can sit at least 2.5 m from the edge of the bath or shower tray, according to Electrical Safety First's bathroom guidance. In a small bathroom there may be no wall that far from the bath. A shaver supply unit can go closer, because it is either SELV, running at a safety extra-low voltage, or built to BS EN IEC 61558-2-5.

RCD protection in bathrooms

Every circuit in or passing through a bathroom or shower room has to be protected by an RCD, the device that cuts the power quickly in a fault. That includes a circuit that only crosses the bathroom on its way to another room. For a mains-voltage fitting in zone 1, it is a 30 mA RCD.

An older consumer unit may have no RCD at all, which can mean upgrading the consumer unit before any fitting goes up. A replacement consumer unit is notifiable work in its own right.

If you are not sure what the board protects, an EICR tests the whole installation, including the switchgear and the earthing, for £100 to £300. Book it before a refit, so a board problem shows up before the tiles go on.

Is bathroom electrical work notifiable?

In England, bathroom electrics come under Part P of the building regulations, which makes 3 kinds of work notifiable: a new circuit, a replacement consumer unit, and any addition or alteration to circuits in a special location. In a bathroom, the special location is the zones.

An electrician registered with a competent person scheme self-certifies the work, tells building control for you and gives you 2 documents: an Electrical Installation Certificate to BS 7671 at the end of the job, and a Building Regulations compliance certificate within 30 days. With an unregistered electrician, a registered third-party certifier is appointed before work starts, or building control is told before work begins and charges to inspect.

Can you do bathroom electrics yourself?

Swapping a bathroom light fitting like for like is not notifiable in England, but the work still has to meet BS 7671 and the fitting needs the right IP rating for its zone. Notifiable work done yourself means telling building control before you start and paying its charge. Electrical Safety First advises using a registered electrician for any installation work.

Bathroom electrics rules in Wales, Scotland and Northern Ireland

The zones are the same in all four nations, because they are part of BS 7671. What changes is how the work is signed off.

Wales

Wales draws the line wider than England. GOV.WALES exempts extra power or lighting points and changes to existing circuits except in a kitchen or bathroom, or outdoors. So in Cardiff or Swansea, a new light point 2 m from the bath, or a fused spur added in the bathroom, has to be notified or done by a registered installer. The compliance certificate follows within 30 days, as in England.

Scotland

Scotland issues building warrants rather than Part P certificates. Minor work such as a new bathroom might not need a warrant, but it must still meet the Scottish building standards. In Edinburgh, Glasgow or Aberdeen, ask the council's building standards team before the electrician starts.

Northern Ireland

Northern Ireland has its own building regulations, with building control run by the district councils. In Belfast, ask the council's building control team whether the bathroom electrics need an application before work starts.

What bathroom electrics cost

In a new bathroom, the electrics are a small line: £250 to £500 of electrician's labour in a full refit, against £1,800 to £4,000 for the whole room's labour.

Electric underfloor heating costs £60 to £85 per m² installed, and in England wiring it near the bath or shower makes it notifiable work. A quote for bathroom electrics should name each fitting, its IP rating and its position, and who certifies the work.