Code of Practice for the Electricity (Wiring) Regulations - 2009 Edition

Code 15 ADVERSE CONDITIONS INSTALLATION
15A Presence of Water (AD) or High Humidity (AB)
(1) Construction of equipment
(a) A wiring system should be selected and erected so that no damage
is caused by high humidity, high condensation or ingress of water
during installation, use and maintenance.
(b) Where water may collect or condensation may form in a wiring
system, provision should be made for its harmless escape through
suitably located drainage points.
(c) Where a wiring system may be subjected to waves (AD6), protection
against mechanical damage should be afforded by one or more of
the methods given in Codes 15E, 15F and 15G.
(2) Conductors and enclosures of wiring installations
(a) Copperclad aluminium conductors should not be used.
(b) All exposed conductors and insulations at terminations and joints of
cables that are insulated with impregnated paper should be suitably
sealed against ingress of moisture.
(c) Every joint in a cable should be suitably insulated and protected
against the effect of moisture or water.
(d ) Overall PVC covering should be provided for mineral insulated cable.
(e) The ends of mineral insulated cables should be suitably sealed with
purposely designed terminations and sealing material, having
adequate insulating and moisture proofing properties throughout
the range of temperatures to which they may be subjected in
service. The mineral insulation of the cables should be thoroughly
dried before the sealing material is applied.
(f ) Every entry to finished ducts, ducting or trunking should be placed
so as to prevent the ingress of water, or be protected against such
ingress.
(g) All metal sheath and armour of cables, metal conduits, ducts,
ductings, trunkings, clips and their fixings, should be of corrosion
resisting material or finish and should not be placed in direct contact
with other dissimilar metals which they are liable to set up
electrolytic action.
In particular, contact between bare aluminium sheaths or aluminium
conduits and any parts made of brass or other metal having a high
copper content should be avoided in damp situation unless the parts
are suitably plated.
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