What are the bathroom zones per BS 7671?

Zone 0 is inside the bath tub or shower tray — only SELV equipment rated IPX7 is permitted. Zone 1 is above Zone 0 up to 2.25m from the finished floor level — equipment must be IPX4 minimum with appropriate protection. Zone 2 extends 0.6m horizontally from Zone 1 — IPX4 equipment with 30mA RCD. Outside zones (beyond Zone 2) has no special IP requirements but 30mA RCD protection is still recommended for all bathroom circuits.

Can I install a socket outlet in a bathroom?

Standard 13A socket outlets are not permitted in Zones 0, 1, or 2. They may be installed outside Zone 2 (more than 0.6m from Zone 1) with 30mA RCD protection — this is typically possible in larger bathrooms. Shaver supply units to BS EN 61558-2-5 (with isolating transformer) may be installed in Zone 2 or outside. SELV sockets (e.g., USB charger at 5V) may be permitted in Zone 2 if appropriately rated.

Is supplementary bonding still required in bathrooms?

Per Regulation 701.415.2, supplementary bonding can be omitted if ALL of the following conditions are met: all circuits in the bathroom are protected by 30mA RCDs, and main protective bonding to all extraneous-conductive-parts is in place. If either condition is not met, supplementary bonding must connect all simultaneously accessible exposed-conductive-parts and extraneous-conductive-parts (pipes, radiators, baths, etc.).

What IP rating do I need for a bathroom light fitting?

Zone 0: IPX7 (protected against temporary immersion). Zone 1: IPX4 minimum (splash-proof from all directions), or IPX5 if water jets are used for cleaning. Zone 2: IPX4 minimum. Outside zones: no specific IP requirement, but IP20 minimum is good practice. For showers with high-pressure jets (e.g., body jets, steam showers), IPX5 is required in Zones 1 and 2.

How are zones measured for a walk-in shower with no tray?

For a shower without a tray, Zone 1 extends 1.2m horizontally from the shower head (measured at the wall) and up to 2.25m from the floor. Zone 2 is 0.6m beyond Zone 1. The 1.2m dimension replaces the tray edge as the boundary of Zone 1. This is important as walk-in showers have larger zone areas than enclosed shower cubicles, affecting where you can position light switches, fans, and other equipment.

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Bathroom Zone Calculator — BS 7671 Section 701

Determine which bathroom zone your equipment is in and the IP rating, voltage, and equipment requirements per BS 7671 18th Edition Section 701.

Installation Type

Type of bath/shower

Shower Head Present?

Affects zone height calculation

Equipment Horizontal Distance

From edge of bath/tray to equipment

Equipment Height from Floor

Height of equipment above finished floor

How We Calculate This

This calculator determines the bathroom zone for a given equipment position based on BS 7671 18th Edition Section 701 zone dimensions.

Zone Dimensions

Zone 0: Inside the bath tub or shower tray
Zone 1: Above Zone 0 to 2.25m from floor, within the perimeter of the bath/tray
Zone 2: 0.6m horizontally from Zone 1 boundary
Above ceiling: If ceiling is below 2.25m, space above is Zone 1 or 2
Walk-in shower: Zone 1 extends 1.2m from shower head
Window in zone: Window recess within a zone is the same zone

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.