Luminaires chosen for use in bathrooms are subject to certain wiring regulations (BS7671: 2008 Section 701) and must be selected and erected, so as to be suitable for the external influences likely to occur at the particular point of installation. Such influences are likely to include steam (leading to condensation), falling drops of water and sprays and/or jets from shower heads.
All luminaries an be assigned an IP (Ingress Protection) rating. This relates to the protection afforded by the light fitting against penetration by solid particles of moisture.
The IP rating consists of two numbers.
The first number relates to the degree of protection against solid particles, the second to the degree of protection against moisture.
For bathroom use, the second number is the most significant.
For example normal household luminaries have a minimum IP rating of 20 (i.e. no protection against moisture).
The required IP rating for light fitting in bathrooms depends on their actual location in the bathroom. The regulations divide the bathroom into zones (see illustrations) which determine the IP rating.
All luminaries used in a bathroom must be protected with an appropriate R.C.D.
Interior of bathtub or shower tray – IPX7 and low voltage supply (max 12v)
Perimeter or bathtub or shower tray up to a height of 2.25m above the floor – IPX4. Use IPX 5 where water jets are used for cleaning purposes.
Perimeter 0.6m wide around zone 1 – IPX4.
Use IPX5 where water jets are used for cleaning purposes.
Outside of Zones
There are no stated requirements for IP. Luminaires should be suitable for their location and provide adequate protection against electric shock.
The IEE Regulations do not make specific reference to wash basins, but in the opinion of the Lighting Association they should be treated as Zone 2 (ie IPX4)