wrote in message
ups.com...
I am wiring my boat with a Perko 1/2/ALL switch and I'm connecting the
hot (+) lead from my accessory panel to the COMMON termial of the
switch (this is the same terminal that runs to the engine as well).

My question is this: Does it matter which battery I connect the
ground (-) to. Seems like a dumb question, I guess, since both
battery grounds are conncected together, but I thought I'd ask anyway
just to be sure.

Many thanks...

The important thing is to make sure the wires you are adding are of
sufficient current carry capability to handle the load.