Review Of What Size Cable For Lighting Ring Main References. These could be a single 1mm2 cable (though 1.5mm2 seems to be more commonly used). It is important to choose the correct size cable when connecting to the mains.

If you have a radial then 2.5mm^2 is good for 20a or 4mm^2 for 32a. You don't need to match the fuse because a ring circuit feeds power from both sides, so (in an ideal perfectly balanced world) you'd only ever draw 15a through each leg. Web i'm needing to calculate the cable size for a long ring main.