What are the bathroom electrical zones in the UK?

BS 7671 (18th Edition) defines three zones in rooms containing a bath or shower. Zone 0 is inside the bath or shower tray. Zone 1 extends from the top of the bath/tray up to 2.25m height and directly above the bath/shower. Zone 2 extends 0.6m horizontally beyond Zone 1 at the same height. Each zone has different IP rating and voltage requirements for electrical equipment.

What IP rating do I need for a bathroom light?

In Zone 0: IPX7 (can withstand immersion). In Zone 1: IPX4 minimum (splash-proof), or IPX5 if water jets are present. In Zone 2: IPX4 minimum. Outside all zones: no special IP rating is required, but IPX4 is still recommended in a bathroom environment. Always use equipment specifically rated for bathroom use.

Can I have a socket outlet in a bathroom?

Standard 13A socket outlets are not permitted in Zones 0, 1 or 2. They can only be installed outside all zones (more than 0.6m beyond Zone 2). The exception is a shaver supply unit conforming to BS EN 61558-2-5, which can be installed in Zone 2. All socket circuits must be protected by a 30mA RCD. Many bathrooms in the UK do not have any socket outlets.

Do I need supplementary bonding in a bathroom?

Under the 18th Edition (Amendment 2), supplementary equipotential bonding is not required if the installation meets automatic disconnection times and all circuits are RCD-protected at 30mA. However, if there is any doubt about the installation meeting these conditions, supplementary bonding should be installed connecting all exposed and extraneous conductive parts (pipes, radiators, bath, towel rail) to the earth terminal.

Is bathroom electrical work notifiable under Part P?

Yes. Any new electrical circuit in a bathroom (a special location under BS 7671) is notifiable under Part P of the Building Regulations. This means you must either use a registered competent person (e.g. NICEIC, NAPIT, ELECSA) or submit a building notice to your local authority. Like-for-like replacements (e.g. swapping a light fitting in the same location and zone) are generally non-notifiable.

Bathroom Electrical Zone Calculator — BS 7671 Zone Distances

Determine which electrical zone a proposed fitting falls in based on its distance from a bath or shower. Includes IP rating requirements, voltage limits and supplementary bonding guidance per BS 7671.

Fixture Type

The bath, shower or basin creating the zones

Fixture Length

Length of bath or shower tray

Fixture Width

Width of bath or shower tray

Fixture Rim Height

Top of bath rim or shower tray (0 for flush tray)

Ceiling Height

Floor to ceiling

Has fixed shower head

Extends Zone 1 to 1200mm from shower head

Proposed Fitting Location

Horizontal Distance from Fixture Edge

Distance from nearest edge of bath/shower

Height from Floor

Height of the proposed fitting

How We Calculate This

This calculator determines which electrical zone a proposed fitting or outlet falls in, based on its distance from the bath or shower per BS 7671 Section 701.

Zone definitions

Zone 0: Inside the bath tub or shower tray basin.

Zone 1: Above Zone 0 up to 2250mm from floor (or to ceiling), extending the full width of the bath/tray.

Zone 2: 600mm horizontally beyond Zone 1, same height limit. For showers with a fixed head and no tray, Zone 1 extends 1200mm from the shower head.

IP rating requirements

Zone 0: IPX7 — SELV 12V only
Zone 1: IPX4 (IPX5 with jets) — fixed equipment only
Zone 2: IPX4 — fixed equipment + shaver socket
Outside zones: No special IP, but 30mA RCD still required

All requirements per BS 7671:2018+A2:2022 (IET Wiring Regulations 18th Edition).

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.