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

(i) materials containing magnesium chloride which are used in the
construction of floors and dadoes;
(ii) plaster undercoats contaminated with corrosive salts;
(iii) lime, cement and plaster, for example on unpainted walls;
(iv) oak and other acidic woods;
(v) dissimilar metals liable to set up electrolytic action.
Application of suitable coatings before erection, or prevention of
contact by separation with plastics, are recognised as a suitable
precaution against corrosion.
(d ) Non-metallic materials used in wiring systems should not be placed
in contact with materials likely to cause chemical deterioration of the
wiring systems. Such materials should either be installed where they
will not be exposed to contact with oil, creosote, and similar
hydrocarbons, or be of a type designed to withstand such exposure.
(e) Overall PVC covering should be provided for mineral-insulated cables
that are exposed to risk of corrosion.
(f ) In onerous dust conditions, enclosures of the wiring installations
should have a degree of protection such that dust cannot enter in
sufficient quantity to interfere with operation of the equipment.
Enclosures built to IP5X or equivalent are considered acceptable.
15D Installation Exposed to Fire or Explosion
(1) General
(a) Electrical equipment and wiring of electrical installations exposed
to potentially explosive atmospheres should be constructed and
protected to the requirements specified for hazardous areas to IEC
60079 or equivalent.
(b) Electrical equipment and wiring of electrical installations in buildings
and premises for the storage, manufacture or packing of dangerous
goods in Categories 1 to 10 must comply with the provisions of
Dangerous Goods (General) Regulations (Cap. 295).
(c) Electrical equipment and wiring of electrical installations in building
and premises for Categories 2 and 5 Dangerous Goods including
those in building and premises for liquid petroleum gas storage and
for petrol filling stations should, in addition to subparagraphs (a) and
(b) above, comply with the requirements specified for hazardous
areas in the Electrical Safety Code Part 1 and 15 of the Energy
Institute/Institute of Petroleum Model Code of Safe Practice for the
Petroleum Industry or equivalent.
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