by ericmark »
Fri Aug 13, 2010 5:30 pm
The regulations take some reading they say:-
528.3 Proximity to non-electrical services
528.3.1 A wiring system shall not be installed in the vicinity of services which produce heat, smoke or fumes likely to be detrimental to the wiring. unless it is protected front harmful effects by shielding arranged so as not to affect the dissipation of heat from the wiring.
In areas not specifically designed for the installation of cables. e.g. service shafts and cavities, the cables shall be laid so that they are not exposed to am harmful influence by the normal operation of the adjacent installations (e.g. gas. water or steam lines).
528.3.2 Where a wiring system is routed below services liable to cause condensation (such as water, steam or gas services), precautions shall be taken to protect the wiring system from deleterious effects.
528.3.3 Where an electrical service is to be installed in proximity to one or more non-electrical services it shall be so arranged that any foreseeable operation carried out on the other services will not cause damage to the electrical service or the converse.
NOTE: This may be achieved by:
(i) suitable spacing between the services. or
(ii) the use of mechanical or thermal shielding.
528.3.4 Where an electrical service is located in close proximity to one or more non-electrical services, both following conditions shall be met:
(i) The wiring system shall be suitably protected against the hazards likely to arise from the presence of the other services in normal use
(ii) Fault protection shall be afforded in accordance with the requirements of Section 411, non-electrical metallic services being considered as extraneous-conductive-parts.
There are more regulations which refer to flora and fauna and if it is likely that the cables will need cleaning then this may also have a bearing.
So a copper hot water pipe would be a problem. A cold water pipe may need a drip loop so water will not follow the cable to the supply point. But there is no regulation that says a cable needs extra protection. There is a big difference between a cable and a wire. A cable will have at least two insulators the outer sheaf and the inner wires will also be insulated. A wire may only have one thin plastic covering. So wiring a house in singles would require conduit everywhere but using twin and earth cables little or no extra protection is required.
