I'm wiring some computer fans behind the fridge in my camper-van to help increase ventilation. As part of this circuit, I have a temperature controlling microcontroller plus relay and a series of SPDT switches to control various aspects of this circuit. Originally, I had simply planned to put all the switches and the microcontroller relay on the hot +12V side of the circuit, but it occurs to be that I could put all this on the ground side of the circuit as well.
This is a vehicle, so the body is tied to ground, but I'm not using that fact for this circuit (i.e., nothing in the circuit attaches to the frame, it's all explicitly wired even for the ground return).
So is there any practical difference between say this circuit:
... and this one, which is identical except that the switches and relays are all on the ground side.
One potential advantage, I suppose, of putting all the control on the ground side is that keeping the hot side simply (a single return wire) decreases the chance of a short to frame, since all the switches and related wiring are at ground potential.