NICEIC Domestic InstallerGuides
Bathroom electrics: common questions
Can you have a socket, a switch, a fan or a light over the bath? Plain answers from Section 701.
Published · Updated · By 2K Electrical Services
Section 701 of BS 7671 covers rooms containing a bath or shower. These are the questions we are asked most often. For how the zones themselves are measured, see our guide to bathroom zones.
Can I have a 230 V extractor fan in zone 1 or 2?
Yes. A fan may be installed in zones 1 and 2 and outside the zones provided it is rated at least IPX4 and the manufacturer says it is suitable for the zone. Where water jets are used for cleaning, IPX5 is required (Regulation 701.512.2).
A fan on the lighting circuit of a windowless bathroom should have its own isolator, otherwise you would be changing the fan in the dark. A fan with an overrun timer needs a triple-pole isolator (live, switched live and neutral), mounted outside zones 0, 1 and 2.
Can I have a socket in the bathroom?
Only if it is at least 2.5 metres horizontally from the boundary of zone 1 (Regulation 701.512.3 in the 18th Edition; older guidance quoting 3 m comes from the 17th Edition). In most London bathrooms that is impossible, so the answer is usually no. The exception is a shaver supply unit to BS EN 61558-2-5, which is permitted in zone 2 away from direct spray.
Can I have a normal light switch?
Yes, outside the zones, which in practice means at least 0.6 m from the edge of the bath or shower, and it must be suitable for the location. Pull-cord switches are allowed in zones 1 and 2 and are the usual choice because the cord copes with humidity and wet hands.
Can I have a light fitting over the bath or shower?
Yes, provided it is rated at least IPX4, which means enclosed and protected against splashing. Outside the zones, more than 0.6 m from the bath or shower edge, no special rating is required, but the fitting must still be suitable for a humid room.
Does everything in the bathroom need an RCD?
Yes. Regulation 701.411.3.3 requires 30 mA RCD protection for all circuits in the location, including lighting, the shower, heated towel rails and underfloor heating. If your bathroom circuits are not RCD-protected, an EICR will record it as a C2 or C3, depending on whether supplementary bonding is in place.
Check the instructions, not just the IP rating
An IP rating tells you about water and dust. It does not tell you whether the manufacturer has approved the product for a particular zone. Check both before you buy.
