I'm converting a VW diesel to run on waste veg oil. Long story short: I need to rig up several switches to a fuse box. In the amateur, grade 3 drawing I made below I'd like to know what gauge wire would be appropriate for the main power on/off switch in addition to knowing what type of switch would be appropriate (how many amps should it be rated for?). I don't anticipate having more then 25 amps in total with all the various devices connected.
Secondly, would a relay be appropriate to implement in this setup? If so then where?
Secondly, would a relay be appropriate to implement in this setup? If so then where?