I'm failing to follow the logic of a couple posts here.
If I put my cutoff switch on the power side of the battery, it will absolutely see all the load that the vehicle is using. The power side, or positive side of the battery's circuit produces, or sees, the load. Lets say I'm using a cutoff switch rated for 50 amps, and my vehicle's electronics need more than the switch is rated for. The switch will eventually overheat and fail. Doesn't matter if you've rated the cables correctly, the switch will be the weak link. Ok, let's look at it from another view. Even if the switch is overrated for the vehicles load demands, and there is an accident that produces a short on the positive side of the battery, the switch will be the weak leak and fail. That's a good thing, as long sat the switch can be closed quickly, but what if it overheats and sticks closed, meaning you cannot open the switch? Not good. If the ground side of the circuit sees as much load as the power side, then why not fuse the grounds, and not the hot side? The ground side will see the voltage, but not the amperage, because the amperage is used by whatever is pulling it. You cannot push electricity. It has to be pulled.
So what if I place the switch on the negative side of the battery? First off, it does not see a load, and will never fail from overloading, and best of all if you remove the ground from the vehicle by switching the negative cable off, then there is never a chance of circuits becoming energized if the switch is off, meaning no "juice" can flow through them, because electricity has to have a ground, or you don't have electricity to start with. I've wired many race cars, and street cars, with cutoff switches, and believe me your taking an unnecessary risk by putting the master cutoff switch on the positive side. Will it work? Sure. Play it safe, and switch the negative side. No ground equals no power.
Did I tell you guys that I make a pretty good living messing with electricity?
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