Dilemma what size 25mm or 35mm
 

Unsure of the size of cable I need to incorporate an isolator switch on my classic myoo does it draw on start up more than 170A if so il need 35mm cable.

Any advice please

I would say well over 170A

Look here: www.vehiclewiringproducts.co.uk

They sell the cable, switches etc and do starter cables in various sizes.

Had a call back fro Parkinsons auto electrical distributor in Grimsby and he said initial crank up is in the region of 300A so 35mm will be fine