A guide to bathroom lighting and regulations

We often advise on bathroom lighting as part of our lighting design service so here is a quick guide to the regulations and how they apply to lighting. This is a handy reference guide, it isn’t an installation guide. For more detailed information refer to the IEE Wiring Regulations (18th Edition) or a qualified electrician.

Bathrooms are inherently wet rooms and electricity and water don’t mix happily. The IEE regulations lay out what fittings are suited for particular applications. The bathroom can be split into 4 zones, Zone 0 to Zone 3. Each zone requires that a light fitting has certain capabilities denoted by its IP Rating.

How are the zones in bathrooms defined?

• Zone 0 : In the bath itself. Fittings in the bath need to be low voltage and rated at least IPx7.
• Zone 1: The area around the bath or shower up to a height of 2250mm from the floor with a radius of 1200mm from the water outlet. Fittings in Zone 1 need a minimum IPx4 rating. If the fitting is 240v, a 30ma residual current device (RCD) must be used to protect the circuit. We would use fittings with a minimum IPx5 in a shower cubicle.
• Zone 2: An area stretching 600mm outside the perimeter of the bath or shower and to a height of 2250mm from the floor. The area round a washbasin within a radius of 600mm from the tap should also be treated as Zone 2. Fittings in Zone 2 need a minimum IPx4 rating.
• Zone 3 (outside zones): Anything outside Zones 0,1 or 2 (subject to specific limits) and where no water jet is likely to be used for cleaning purposes. No specific IP rating is required. If water jets are used for cleaning in Zones 1,2 or 3, a fitting must have a minimum IPx5 rating.

Understanding IP ratings in bathroom lighting regulations – what do those IP numbers mean?

The IP or Ingress Protection rating is a measure of protection against solids and liquid. The first number is the protection against solids, the second the protection against liquids. In both cases the higher the number, the higher the degree of protection. When we refer to IPx4 we are referring to a fitting where the protection against liquid ingress is 4 (and the protection against solids is not specified).

x0 – no protection from liquids
x1 – protection against vertically falling drops of water(e.g. condensation)
x2 – protection against direct sprays of water up to 15 degrees from vertical
x3 – protection against direct sprays of water up to 60 degrees from vertical
x4 – protection against water sprayed from all directions – limited ingress permitted
x5 – protected against low pressure jets of water from all directions – limited ingress permitted
x6 – protected against high pressure jets of water (use on ship deck) – limited ingress permitted
x7 – protected against the effects of immersion between 15cm and 1m
x8 – protected against long periods of immersion under pressure