T 3.5 Inadvertent damaging of cables

The risk of inadvertent damage increases with the lack of protection provided in the layout of cables. Such damage does not necessarily result in an immediate breakdown of connections. It is also possible that inadmissible connections are established accidentally. Typical examples of such damage are:

within the building:

• an unembedded flexible device cable is yanked out with the foot;

• damaging of concealed (buried) cables by drilling or nailing;

• incursion of water into windowsill ducts;

• incursion of water into conduit subways (floor ducts) during cleaning of the building;

• damaging of exposed lines (on walls or floors) during the transport of bulky or heavy objects.

externally:

• damage caused during below-grade construction, through both manual excavation and excavator use;

• incursion of water into underground lines/buried cables.

Example:

In a pedestrian precinct, the charwoman employed by a small shop had made a habit of pouring the used water directly in the PTT-cable inspection manhole. Although the water evaporated, the dirt and soap residues deposited on the cables had to be removed with great expenditure of time and effort when work had to be carried out.

• damaging of cables by rodents;

• damaging of ducts and cables by roots (the roots of a tree are strong enough to crush cables);

• damage caused by the exceeding of admissible traffic loads (pipes may burst, cables may be sheared