7.3.2 - Special requirements for swimming pools

Appliance and sockets for use in these high-risk areas must be separated extra-low voltage (SELV) type, at a potential not exceeding 12 V ac or 30 V dc. Such equipment must be protected to level IP2X, which means that it must be impossible to touch live parts with a finger, or must have insulation capable of withstanding a voltage level of 500 V r.m.s. for one minute. The safety source (a transformer in most cases), must be installed outside zones A, B and C. An exception is the supply to floodlights (often they will be under water) which can be fed at up to 18 V, if in zones B or C, or 12 V if in zone A (submerged), each floodlight being powered by a separate transformer or a separate secondary winding of a transformer having multiple secondary windings.

Normal luminaires are not permitted in zones A or B, so general illumination is best provided by luminaires mounted higher than 2.5 m above floor level. This is zone C, where protection must be by electrical separation (see {5.8.4}) or by 30 mA residual current device(s). If RCDs are used, care must be taken to ensure that devices are not tripped by high leakage currents on starting; the use of multiple circuits, each with its own RCD, is advised. Attention is drawn to the difficulty of servicing luminaires mounted above the pool.

Usually, protection against direct contact will be by means of earthed equipotential bonding and automatic disconnection of the supply in the event of a fault (the same as for most other installations), and the special requirements are:

1. - all extraneous conductive parts, including non-insulating floors, must be bonded together and to earth. If the floor within zones B and C is not insulated or if a PME supply is used (see{5.6}) a metal grid must be installed in the floor and connected to the local supplementary bonding. The exception to this is any SELV system, which must remain unconnected to the main earthing system.

2. - the earth fault loop impedance must be low enough so as to allow disconnection within 0.4 s (see {5.3}).

In no case is it permissible to rely for protection against direct contact on obstacles, placing out of reach, a non-conducting location or earth-free equipotential bonding. If wiring is run on the surface it must not be metallic sheathed and must not he run in metal conduit or metal trunking, except in zone C.

Enclosures used for wiring systems or appliances at swimming pools are subject to special requirements, which depend on whether water jets will be used for cleaning purposes. If they will be used, protection must be to IPX8, (submersion in water), within the pool (Zone A) and IPX5, which means that there must be effective protection against such water jets (see {Table 2.1}). If water jets will not be used, protection depends on the zone (see {7.3.1}) in which the system or appliance is situated. The requirements are:

Zone A
IPX8, which means protection from submersion in water,

Zone B
IPX4, so that protection is provided against splashing water, and

Zone C
indoor pools, IPX2, which gives protection against dripping water when inclined at 15°; and outdoor pools, 1PX4, which gives protection against splashing water.

There must be no switchgear, control gear or accessories installed within zones A or B, except for small pools where socket outlets are necessary and cannot possibly be installed outside zone B. In this case, BS 4343 socket outlets may be installed provided they are at least 1.25 m (arms' reach) outside zone A, are at least 0.3 m above the floor, and are protected by an RCD with a 30 mA rating or are protected by electrical separation [413-05] with the necessary isolating transformer situated outside zones A, B and C. Wiring must not be metallic sheathed, or enclosed in metallic conduit or trunking if run on the surface. Joint boxes may be used, but they must be inaccessible if installed in zones A or B. Instantaneous water heaters complying with BS 3456 may be installed in zones B and C.

Socket outlets (in zone C only - but see above for small pools) must be to industrial standard BS 4343, and a shaver outlet to BS EN 60742 may also be installed in zone C (5.8.4). If electric floor heating is used around a pool, it must have its metal sheath, or a covering metal grid if there is no metallic sheath, connected to the local equipotential bonding. Fire alarm, audio and public address equipment should ideally be outside zones A and B, but where this is not possible must be more than 1.25 metres outside zone A. Loudspeakers must be out of reach of anyone in the water or at the poolside, and if portable microphones are used they must be connected by way of a suitable isolating transformer. Radio microphones will reduce the danger of shock. Hard wired telephones are not permitted in any zone, and if required, cordless telephones must be used with the base unit outside the zones. Where the basin of a fountain is not intended to be occupied by people, installations in zones A and B may be protected by electrical separation (see {5.8.4}) or by automatic disconnection of the supply using an RCD with an operating current not exceeding 30 mA.