4.3.14 - The effects
of animals, insects and plants
Cables may be subject to damage by animals
and plants as well as from their environment. Rodents in
particular seem to have a particular taste for some types
of cable sheathing and can gnaw through sheath and insulation
to expose the conductors. Cables impregnated with repellent
chemicals are not often effective and may also fall foul
of the Health and Safety Regulations. Rodents build nests,
often of flammable materials, leading to a fire hazard.
Care should be taken to avoid cable installation along possible
vermin runs, but where this cannot be avoided, steel conduit
may be the answer.
Mechanical damage to wiring systems by
larger animals such as cattle and horses can often be prevented
by careful siting of cable runs and outlets. Attention must
also be given to the fact that waste products from animals
may be corrosive. Access by insects is difficult to prevent,
but vent holes can be sealed with breathers. Damage by plants
is a possible hazard, the effect of tree roots on small
lighting columns being an obvious problem area.