Bathroom Electrics

1. Bathroom Electrics

The modern UK standards and regulations for electrical wiring no longer differ substantially from those in other European countries, but differ significantly from other countries with

  1. ring circuits
  2. fused plugs
  3. switched sockets
  4. historic wiring colors
  5. asymmetric supply-voltage tolerances
Earlier British wiring rules in bathrooms used to be far more restrictive, leading to British peculiarities in bathrooms such as the use of cord switches. The 2001 edition of the Wiring Regulations is more flexible now, placing restrictions on bathroom installations that are now more similar to those in other European countries

2. Bathroom Zones

The installation of electrical devices in bathrooms and shower rooms is regulated in Section 601 of BS 7671, and Part B of the Building Regulations. For such rooms, four special zones are defined, in which additional protection is required for electrical facilities: Zone 0 is the smallest rectangular volume that contains the bathtub, shower basin, etc. Zone 1 is the area above Zone 0, up to a height of 2.25 m above the floor. Zone 2 is the area above Zone 1 up to a height of 3 m, as well as the area that is horizontally within 0.6 m from Zone 1. Zone 3 is the area above Zone 2 up to a height of 3 m, as well as the area that is horizontally within 2.4 m from Zone 2.

Within Zone 0, only Separated Extra Low Voltage devices are permitted. Any AC transformer supplying such a device must be located outside Zones 0-2. The minimum required ingress protection rating in Zone 0 is IPX7 and IPX4 in Zone 1 and 2. If water jets are likely to occur, at least IPX5 is required in Zone 1-3. Otherwise, in Zone 3 and beyond, an ingress protection rating of IP20 is the minimum required. Equipment in Zone 1-3 must be protected by a 30 mA residual-current circuit breaker (except for shower pumps and shower heaters, where the use of an RCD is so far only recommended). Shaving sockets (with isolating transformer) are permitted in Zone 2 if direct spray from a shower is unlikely, even if they are only IP20. In a bathroom or shower room, such shaving sockets are the only sockets permitted in the entire room. In any other room with a bathtub or shower, normal sockets are permitted as long as they are outside Zone 3.

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