16th Edition (reference only) – NOW superseded by the 17th Edition IEE Regulations.

chapter 5

chapter 6

Special Installations
  --1. - Introduction --2. - Bath tubs and shower basins
  --3. - Swimming pools --4. - Sauna rooms
  --5. - Installations on construction sites --6. - Agricultural & horticultural
--7. - Restrictive conductive locations --8. - Earthing for function & protection
--9. - Caravan, motor homes, caravan parks 10. - Highway power & street furniture
11. - Heating appliances & installations 12. - Discharge lighting
13. - Underground & overhead wiring 14. - Outdoor installations & garden buildings
15. - Installations of machines & transformers 16. - Reduced voltage systems
17. - Marinas 18. - Medical locations
19. - Exhibitions, shows and stands

7.14.2 - Garden installations

Increasing use is being made of electrical supplies in the garden, for pond pumping systems, lighting, power tools and so on. The following points apply:

1. - Socket outlets installed indoors but intended to provide outdoor supplies must be protected by an RCD with a maximum operating current of 30 mA. Any portable equipment not fed from a socket outlet must also be protected by an RCD with a 30 mA operating current. Outdoor sockets also require the same RCD protection and must also satisfy IP44 requirements (see {2.4.3}).

2. - Garden lighting, pond pumps and so on should preferably be of Class Ill construction, supplied from a SELV system and having a safety isolating transformer supply. Where 240 V equipment must be used, it should be Class II double insulated (no earth) and should be suitably protected against the ingress of dust or water. If accessible Class I equipment is used its supply system must have an earth fault loop impedance low enough to allow disconnection within 0.4 s in the event of an earth fault.

3. - Earthing must be given special attention. All buildings must be provided with 30 mA RCD protection, but the Electricity Supply Company should be consulted to ascertain their special requirements if the supply system uses the PME (TN-C-S) system. Where the supplier does not provide an earth terminal, each outbuilding must be provided with an adjacent earth electrode.

4. - Outbuildings are often of light construction and therefore are subject to extremes as far as temperature swings are concerned. It is therefore important to bear this in mind when selecting equipment and components.

5. - Extraneous conductive parts of an outbuilding which may become live due to a fault should be bonded to the incoming protective conductor.

6. - Every outbuilding with an electrical supply should be provided with a means of isolation to disconnect all live conductors including the neutral.

7. - All outbuildings where protection against direct contact is by earthed equipotential bonding and automatic disconnection of the supply should have a disconnection time in the event of an earth fault which does not exceed 0.4 s.

8. - Cables which are not buried must be shielded from direct sunlight, whose ultraviolet content will affect plastics. Cables with ultra-violet protected sheaths may be used; the preferred colour for such cables is black.

9. - Large garden ponds present a particular problem because of the probability that sooner or later people will fall into them. In such a case, the Regulations applying to swimming pools (see {7.3}) should be applied. Pumps and lighting should be SELV with the safety source at least 3.5 m outside the edge of the pond. All cables in the pond must be in ducts or conduits which are built into it and not be allowed to lie loose. All pond equipment must be protected to IP55 (see {2.4.3}) or better.


Return to top of page

Extracted from The Electricians Guide Fifth Edition
by John Whitfield

Published by EPA Press Click Here to order your Copy.

Click here for list of abbreviations