Armoured cable

The typical construction of an SWA cable can be broken down as follows: The PVC version of SWA cable,[5] described above, meets the requirements of both British Standard BS 5467 and International Electrotechnical Commission standard IEC 60502.

The use of the armour as the means of providing earthing to the equipment supplied by the cable (a function technically known as the circuit protective conductor or CPC) is a matter of debate within the electrical installation industry.

Primary concerns are the relative conductivity of the armouring compared to the cores (which reduces as the cable size increases) and reliability issues.

Recent articles by authoritative sources have analysed the practice in detail and concluded that, for the majority of situations, the armouring is adequate to serve as the CPC under UK wiring regulations.

As a result, LSZH cables are now recommended for use in highly populated enclosed public areas.

Early cables carrying telegraph used iron wire armouring, but later switched to steel.