If you’re planning a bathroom renovation or want to add a light, shaver socket, or extractor fan, you’ll come across the concept of electrical zones. It sounds technical, but the idea is straightforward: different areas of a bathroom carry different levels of risk from water, so different rules apply to each one.
Why do bathrooms need special electrical rules?
Water and electricity are a dangerous combination. In a bathroom, the risk varies depending on how close you are to the bath or shower. The zone system — set out in BS 7671, the IET Wiring Regulations — divides the bathroom into areas based on their proximity to water sources, and sets minimum standards for any electrical equipment installed in each zone.
The zones also determine what work is notifiable under Part P of the Building Regulations — the rules that govern electrical safety in domestic buildings in England and Wales.
Zone 0 — inside the bath or shower
Zone 0 is the area inside the bath itself, or the base of the shower tray. This is the highest-risk area. Any electrical equipment installed here must be rated to at least IPX7 (protected against immersion in water). In practice, very little electrical equipment is ever installed in Zone 0 — the main exception is certain types of low-voltage lighting specifically designed for underwater use.
Zone 1 — above the bath or shower
Zone 1 extends directly above the bath or shower tray, up to a height of 2.25 metres from the floor. Equipment installed here needs a minimum IP rating of IPX4 (protected against water splashing from any direction). Lighting designed for bathroom use is commonly installed in Zone 1 ceilings. Only safety extra-low voltage (SELV) equipment or equipment specifically rated for Zone 1 should be used here.
Zone 2 — the surrounding area
Zone 2 covers the area 0.6 metres horizontally outside Zone 1, up to 2.25 metres from the floor. This includes the wall areas beside the bath or shower. Equipment here needs a minimum rating of IPX4. Standard light fittings without the appropriate IP rating are not suitable for Zone 2.
Outside Zones 0, 1, and 2 — such as on a wall some distance from the bath — the usual rules apply, though it’s still good practice to use fittings appropriate to a damp environment.
What is an IP rating?
IP stands for Ingress Protection. The rating tells you how well a piece of equipment is sealed against solid objects and liquids. The first digit covers dust, the second covers water. So IPX4 means it’s tested against water splashing from any direction, while IPX7 means it can survive immersion. When buying bathroom fittings, always check the IP rating — it should be clearly stated on the packaging.
What electrical work can go in a bathroom?
Shaver sockets are permitted in bathrooms — but only where they comply with BS EN 61558-2-5 and are positioned outside Zone 1. You cannot install a standard 13A socket outlet inside a bathroom; they’re not permitted anywhere in the room except in a separate compartment (like an en-suite WC area) that’s separated from the bath or shower.
Extractor fans are commonly installed in Zone 1 and 2 — provided they carry the correct IP rating. Pull-cord switches are used in bathrooms precisely because they keep the switching mechanism away from the water zones.
Underfloor heating is also common in bathrooms and perfectly safe when installed correctly by a qualified electrician with appropriate zone-compliant thermostats. We cover the circuit, testing and thermostat details in what electrics electric underfloor heating needs.
Does bathroom electrical work need to be certified?
Yes. Most electrical work in a bathroom is notifiable under Part P, which means it either needs to be carried out by a registered electrician who can self-certify, or submitted to your local authority for inspection. A registered electrician will issue you with a Building Regulations compliance certificate after the work is done — you’ll need this if you ever sell the property.
To find a qualified installer, check the NICEIC register or NAPIT’s member directory. We’re NICEIC registered — you can read more about what that means in our post on what the NICEIC is.
Is bathroom electrical work picked up on an EICR?
Yes. When an electrician carries out an Electrical Installation Condition Report (EICR), they’ll check that bathroom fittings are zone-compliant and that RCD protection is in place for circuits supplying the bathroom. Non-compliant fittings or missing RCD protection are common reasons for a C2 (potentially dangerous) code on a report.
If your RCD trips when you’re using bathroom appliances, that’s a sign something needs attention — our guide to why your RCD keeps tripping covers the common causes.
If you’re planning bathroom electrical work in Bristol or South Gloucestershire, get in touch with us for advice or a quote. We’ll make sure everything is installed safely, correctly zoned, and fully certified.
