Bathroom Zone Calculator — BS 7671 Section 701

Zone 0 is inside the bath tub or shower tray — only SELV equipment (≤12V AC / 30V DC) rated IPX7 is permitted. Zone 1 is the space directly above Zone 0, up to 2.25m from the finished floor level (or the highest fixed water outlet, whichever is higher), bounded by the vertical surface around the bath/tray — it has no horizontal extent beyond the bath edge. Equipment must be IPX4 minimum. Zone 2 is the 0.6m strip measured horizontally from the Zone 1 border (the bath/tray edge), also IPX4. Outside the zones there is no special IP requirement, but 30mA RCD protection is mandatory for all bathroom circuits.

Standard 13A socket outlets must be at least 2.5m horizontally from the boundary of Zone 1 (Regulation 701.512.3) — being merely outside Zone 2 is not enough, so a socket 1m from the bath edge would still be non-compliant. This 2.5m exclusion is only practical in larger bathrooms; the socket must have 30mA RCD protection. Shaver supply units to BS EN 61558-2-5 (with isolating transformer) are not classed as socket outlets and may be installed in Zone 2 or outside. SELV outlets (e.g., a 5V USB charger) may be permitted in Zone 2 if appropriately rated.

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.). Use our Bonding Conductor Calculator to size the bonding correctly.

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. See our IP Rating Calculator for detailed IP code explanations.

For a shower without a basin or tray (e.g. a wet room), BS 7671 Regulation 701.32.3 says there is no Zone 2. Instead, Zone 1 is enlarged to a 1.2m radius measured horizontally from the fixed water outlet, up to 2.25m from the floor. The 1.2m dimension replaces the tray edge as the boundary of Zone 1, and beyond 1.2m the area is outside the zones (no special IP requirement, but 30mA RCD protection still applies). This enlarged Zone 1 affects where you can position light switches, fans, and other equipment.