This comes under the realms of SPECIAL LOCATION and is classified as a room containing a shower with or without a shower basin or a room containing a bath tub. It is classed as a 'Special Location' due to the higher than usual risk of electrical injury due to low body resistance when wet.
The Regulations define ZONES for rooms containing a bath tub or shower with or without a basin. Only certain accessories or fixed appliances can be reasonably located in certain Zones dependent on the Index of Protection of the individual item. The following describes the Zones:
Zone 0 is the interior of the bath tub or shower basin.
For showers without a basin, the height of zone 0 is 0.10 m and its surface extent has the same horizontal extent as
zone 1
Zone 1 is limited by:
(i) the finished floor level and the horizontal plane corresponding to the highest fixed shower head or water
outlet or the horizontal plane lying 2.25 m above the finished floor level, whichever is higher
(ii) the vertical surface:
(a) circumscribing the bath tub or shower basin
(b) at a distance of 1.20 m from the centre point of the fixed water outlet on the wall or ceiling for showers
without a basin.
Zone 1 does not include zone 0.
The space under the bath tub or shower basin is considered to be zone 1. However, if the space under the bath tub or
shower basin is only accessible with a tool, it is considered to be outside the zones.
Zone 2 is limited by:
(i) the finished floor level and the horizontal plane corresponding to the highest fixed shower head or water
outlet or the horizontal plane lying 2.25 m above the finished floor level, whichever is higher
(ii) the vertical surface at the boundary of zone 1 and the parallel vertical surface at a distance of 0.60 m from
the zone 1 border. .
For showers without a basin, there is no zone 2 but an increased zone 1 is provided by the horizontal dimension of
1.20 m.
Bath tub
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Bath tub, with permanent fixed partition
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Shower basin
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Shower basin, with permanent fixed partition.
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Shower without basin
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Shower without basin, but with permanent fixed pasrtition
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Bath tub
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Shower basin
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Shower without basin, but with perninent fixed partition.
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Bathroom Zones and Switches, Controls,Accessories
Care should be taken as to where accessories and fixed current using equipment are installed within the bathroom in order to satisfy the Wiring Regulations. The following are examples of the most common accessories and fixed current using equipment which are permitted in different zones:-
Zone 0 IPX7 equipment, NO switches or accessories.
Zone 1 IPX4 Equipment and SELV switches with the source outside all the zones.
Zone 2 IPX4 Anything from Zone's 0,1 Unswitched spurs, flex outlets. Shaver points that are to BS EN 61558-2-5 can be fitted in Zone 2 providing they are not in the direct line of the water jet.
Outside Zones Anything from Zone's 0, 1, & 2. Anything goes providing it is deemed suitable to be used in the bathroom and is fixed, NOT portable. Sockets, except SELV sockets, must not be fitted closer than 3 metres horizontally from the border of Zone 1
Current using equipment
Zone 0
The equipment meets IPX7 and relevant standards according to manufacturers instructions.
It is fixed and permanantly connected to a supply.
The equipment is connected to a SELV supply with the source outside the zones.
Zone 1
Only the following can be fitted providing they are suitable for the zone, IPX4, or suitable according to manufacturers instructions:
Whirlpool units
Electric Showers
Shower Pumps
Equipment protected by SELV
Ventilation equipment
Towel Rails
Water heater appliances
luminaires.
Electric floor heating
For electric floor heating systems, only heating cables according to relevant product standards or thin sheet sheet flexible heating elements according to relevant equipment standard shall be erected provided that they have either a metal sheath or a metal enclosure or a fine mesh metallic grid. The fine mesh metallic grid, metal sheath or metal enclosure shall be connected to the protective conductor of the supply circuit. Compliance with the latter requirement is not required if the protective measure SELV is provided for the floor heating system.
For electric floor heating systems the protective measure 'protection by electrical separation' is not permitted.
RCD's
All electrical items in the bathroom should be RCD protected at 30mA.
Manufacturers of certain electrical equipment ask for RCD's to be fitted for the supplementary protection of the equipment, read the instructions.
NOTE: If RCD's are not installed and/or protective equipotential bonding is not in place then local supplementary bonding must be installed.
Supplementary Bonding
All electrical sources, lights, electric heaters, showers etc. have to be connected together along with the pipe work. It does not have to be one continuous cable as long as there is an electrical continuity between everything locally within the room. The cable size is normally 4mm² and you should use the BS951 Earthing Clamps on pipe work. If you have a new shower fitted in your bathroom you will more than likely have to have this bonding updated which of course will add additional costs to the installation. By having everything earthed together, should there be a fault to earth, there will be the same potential all round the bathroom thereby any electric shock should be minimal.
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