Section 701 rules for rooms containing a bath or shower: the zones, 30 mA RCDs, IP ratings, SELV limits and when supplementary bonding may be omitted.
Why locations with a bath or shower are special
Section 701 of BS 7671 applies extra requirements because a wet body has reduced contact resistance, increasing the risk of electric shock. Distances from the water are divided into zones.
The zones
- Zone 0: the interior of the bath tub or shower basin
- Zone 1: the area above zone 0 up to 2.25 m above the finished floor level
- Zone 2: a band extending 0.6 m horizontally beyond zone 1
Protection within the location
- every circuit serving the location must have 30 mA RCD additional protection
- equipment exposed to splashing must be at least IPX4, rising to IPX5 where water jets are used for cleaning
- in zone 0 only SELV is permitted, limited to 12 V AC or 30 V ripple-free DC, with the source placed outside the zones
Socket-outlets
- 13 A socket-outlets must be at least 3 m horizontally from the boundary of zone 1
- SELV socket-outlets and shaver supply units to the relevant standard may be installed closer
Omitting supplementary bonding
Local supplementary equipotential bonding may be omitted only where all of the following are met:
- all circuits of the location have 30 mA RCD protection
- all extraneous-conductive-parts are connected to the main protective bonding of the installation
- all final circuits satisfy the required disconnection times