The SWA Armoured Cable size is from 1.5mm2 to 300mm2 For 2 core – single phase a.c., 3 & 4 core – three phase a.c. – ratings do not apply if the cable is protected by a semi-enclosed fuse to BS3036. For cables of 5 cores and above it is assumed only 2 cores are loaded simultaneously (ie live and neutral) and the 2 core rating should be taken. In instances where several cores are loaded simultaneously, the following rating factors should be applied to the 2 core current rating.