Colin asks this question, which concerns SWA cable to BS 6724, and whether the type has been tested and verified as having any fire resistance. It has been answered by BASEC (Theme – Cable, Wiring and Wiring Accessories):
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Question: SWA cable (e.g. BS 6724) has a certain inherent fire resistance by virtue of its construction, though it is not formally certified to any test standard.
Has this ever been tested or verified?
Is there any operational evidence of ANY ability of SWA cable to withstand elevated temperatures or direct flame?
Answer: Normal steel wire armoured (SWA) cables, either PVC sheathed (BS 5467), or the type having low emission of smoke and corrosive gases when affected by fire (BS 6724), do not have a fire resisting property.
BS 6724 cables are subjected to a vertical flame spread test which looks at the possible contribution of such a cable to the growth and spread of a fire, but this is not a fire resistance test.
There is a type of SWA cable that is specifically designed to withstand fire and provide fire resistance for circuit integrity purposes - BS 7846. Although based on the same construction and materials as BS 6724 cables, BS 7846 cable has additional layers of material intended to provide on-going circuit integrity for a specified period during a fire. It is subjected to a number of additional fire resistance / circuit integrity tests, which a BS 5467 or BS 6724 cable would not be able to pass.
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