Wiring in Wet Areas
Special restrictions that exist for electrical work in wet areas
Where there is the greatest danger of electrocution…
Special restrictions exist especially for electrical work in wet areas, where there is the greatest danger of electrocution.
Any cabling, running through a room containing a bath or a shower, needs to be RCD protected. 230 V 13 A socket outlets are allowed, but only if they are at least 3 m horizontally from the boundary of zone 1.
An exception to this requirement is a shaver supply unit, complying with BS EN 61558-2-5 which, although it does not meet the requirements of IP4X, is permitted in zone 2, but must be located where direct spray from showers is unlikely.
A plate switch is allowed outside the zones of a bathroom. A switch should be at least 0.6 m from the edge of the bath or shower (outside the zones) and must be suitable for the location – otherwise a pull cord should be used.
230 V fittings may be installed above a shower or bath, but they must be at least IPX4. If not, they need to be installed more than 0.6 m from the edge of a shower basin or bath (outside the zones).
An extractor fan, supplied from a lighting circuit for a bathroom without a window, should have its own means of isolation.
Electrical appliances (except shaver points), including electric showers, light fittings and ventilation fans, must have levels of moisture and mechanical protection, defined by IP or Ingress Protection numbers. The IP rating has the letters IP followed by two characters. The first specifies the degree of protection against particles or solid objects. The second specifies the degree of protection against liquids.
The I.E.E. Wiring regulations (BS 7671: 2001 Section 601) has mandatory requirements for areas containing a bath or shower. These safety standards are measured in zones, with the requirements for each zone being based on the perceived degree of risk of electric shock.
There are four wet zone categories: 0, 1, 2 and 3.
- Zone 0: Inside the bath or shower. Any fittings used here must be SELV (max 12V) and be rated IPX7 (protected against immersion in water).
- Zone 1: Above the bath or shower to a height of 2.25m. A minimum rating of IPX4 is required.
- Zone 2: The area stretching to 0.6m outside the bath or shower and above the bath or shower if over 2.25m. An IP rating of at least IPX4 is required.
- Zone 3: Anywhere outside zones 0, 1 and 2. Where water jets are not to be used for cleaning purposes, the general rules of BS7671 apply. For detailed information, refer to the I.E.E. Wiring regulations (BS 7671: 2001 Section 601).
For the latest I.E.E. regulations click here
DIY electrical work, rewiring work and alterations to electrical installations are covered by the Building Regulations Part P: Electrical Safety. You can undertake minor additions or alterations to existing circuits; adding a new socket or light fitting without having to make a Building Regulations application. Providing it is not in a wet area, like a kitchen or bathroom, outdoors, or connected directly into the consumer unit. Repairs, replacements and maintenance work are not notifiable.
You can undertake other rewiring work yourself too, including in wet areas, but you must make a Building Regulations application (current cost around £150 including inspection fee) and arrange to have the work inspected both before and after completion by a qualified electrician registered with one of the competent persons schemes. They will check the work complies with the regulations and issue a safety certificate. Not all electricians offer this service and many are not prepared to sign off someone else’s work. There is a risk with this approach, both from a safety and a financial perspective.
Remember that the wiring regulations require all cables buried in walls to run either vertically or horizontally from sockets. This really helps the follow-on trades who may be screwing fixings into walls for curtain rails, radiators, shelving or kitchen units. Some amateurs run cable at angles across walls in order to save a little cable without realising the potential danger this may cause.
For advice on wiring in wet areas, speak to the experienced team at Pure Electric.