T 1.6 Burning cables

When a cable catches fire, either by spontaneous ignition or kindling, this can have a variety of consequences:

• The connection may go down.

• The formation of aggressive gases may occur. These could not only be corrosive and hence affect IT and communications equipment, but they could also be toxic, resulting in personal injury (e.g. poisoning).

• Cables with non fire-resistant or self-extinguishing insulation material may help the fire to spread. Even fire sealing cannot prevent this completely, but merely delay the spread of the fire.

• In the case of close-packed lines, there may be smouldering fires which can remain undiscovered for a prolonged period of time, resulting in the spreading of the fire long before it breaks out into the open.

Example

In an east German administrative building the existing electrical cables were not replaced for cost reasons but were unwisely overloaded. The necessary modification work was not carried out as the staff were expecting to be shortly relocated to a new administrative building.

The overloaded lines heated up and because they were laid so close together an accumulation of heat occurred. This eventually resulted in a smouldering fire. The fire was only discovered when the cables failed due to the huge amount of heat. It took two days to restore the workstations affected by the fire to a condition where they could be used again.