However else you choose to handle things, our experience regarding possible lightening strikes suggests that using a double-pole toggle switch to interrupt both negative and positive connections may offer a degree of protection. We have added these at every instrument close to the device. Get these switches from any marine chandlery
. All modern electronic devices have software
power switches on only the + side. A strike can easily blow right through the power-on circuit and the other side is hard wired to ground.
Typical Marine wiring will be:
Batteries to a main panel
Main Panel - main disconnect breaker
Main power key-lock power on. (possible A or B battery switches)
Distribution on the main panel to breakers for specific circuits.
Breakers normally are sized to protect the wires although the breaker may be smaller.
Circuit labeled INSTRUMENTS may power a remote
terminal strip for distribution to users.
Each user probably has a vendor furnished in-line fuse of the proper size to protect the device. In the nav station I like to replace these with panel mount fuses
Boat negative ground will land on terminals - eventually gathered to the main ground.
Main ground to a shunt.
Shunt to battery negative.
You should only use marine rated tinned wire. Not so important on the Great Lakes
air will degrade bare copper multi-strand wire. This makes it difficult to make a good connection later and can cause hot spots in a crimp connector. If you are inspected or need to make a claim for fire, proper wire could be a big deal.