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

conduit or duct and be buried at a sufficient depth to avoid being
damaged by any disturbance of the ground reasonably likely to occur.
(d ) A wiring system buried in a floor should be sufficiently protected to
prevent damage caused by the intended use of the floor.
(e) Where a cable is installed under a floor or above a ceiling it should be run
in such a position that it is not liable to be damaged by contact with the
floor or the ceiling or their fixings. Cable should incorporate an earthed
metallic sheath suitable for use as a protective conductor or should be
protected by enclosure in earthed steel conduit securely supported, or by
equivalent mechanical protection sufficient to prevent penetration of the
cable by nails, screws, and the like.
(f ) Where a cable is to be concealed within a wall or partition, the concealed
cable should incorporate an earthed metallic covering which complies
with the requirements of this CoP for a protective conductor of the circuit
concerned, or should be enclosed in conduit, trunking or ducting
satisfying the requirements of this CoP for a protective conductor, or by
mechanical protection sufficient to prevent penetration of the cable by
nails, screws and the like. In case of a concealed bonding conductor, the
conductor should be installed in accordance with the above requirements
for a cable, or be installed within 150 mm of the top of the wall or
partition or within 150 mm of angle formed by two adjoining walls or
partitions in a straight run, either horizontally or vertically to the point or
accessory.
(g) For where PVC concealed conduit system is applied, all conduits installed
and concealed inside floor slab, wall or partition for cable wiring shall
have concrete, cement or plaster cover of thickness not less than 30 mm
(or 25 mm for short PVC concealed conduit of length less than 150 mm
that is installed within 150 mm of the top of the wall/partition or within
150 mm of an angle formed by two adjoining walls/partitions) to prevent
penetration of the cables inside conduits by nails, screws and the like.
15F Vibration (AH)
A wiring system supported by, or fixed to a structure or equipment subject to
vibration of medium severity (AH2) or high severity (AH3) should be suitable
for the conditions and in particular shall employ cables with fixings and
connections suitable for such a situation.
15G Other Mechanical Stresses
(a) A wiring system should be selected and erected so as to minimise during
installation, use and maintenance, damage to the sheath and insulation
of cables and insulated conductors and their terminations.
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