Headlight cable amp rating

[RichardHyde]

Dear all,

I’ve got 4 fused relays mounted under the dash feeding each of the 4 lights. To keep the colour scheme the same as standard, I’ve purchased blue / white and blue / red cable from CBS. This cable is rated as 16.5A, 1mm squared, 32/0.20 2mm diameter.

From school physics using P =VI this rating seems ample. Is it ok in the real world ?

Thanks, Richard

[Carledo]

This is exactly the cabling I used on the Dolomega headlights and it seems to be fine so far.

I used 2 relays, 30a dip and 40a main, 4 fuses (LH dip, RH dip, LH main and RH main). Just to be on the safe side, on the main beam I used 2 wires from the fuse for each side so each main beam bulb had its own lead. The dip fuses are 10 amp and the main beam fuses are 20 amp, bulbs are 65/55w in the outers and 75w inners Each main beam fuse is fed from the relay (about 6") with a chunk of wire taken from the bottom of the original headlight loom (28/012?) which used to supply all 4 main beam filaments on the original, so should be good enough for 2 uprated ones!

I think I actually did the sums on this and i've gone slightly overkill. But, all things considered, I prefer to have the electrical system better than it needs to be, rather than just good enough or marginal! If anything DOES go wrong, the fuses should blow before anything else even gets warm.

Steve