Gene Cramer of Milwaukee, Wisconsin, asks:
“Where can I get a galvanic isolator of the sort you mentioned in your excellent piece on wiring a boat for shore power? Also, the circuit you described in that piece doesn’t seem to provide ground-fault protection either for the battery charger or for other branch loads, such as the water heater, which would be hard-wired to the CB panel. Shouldn’t one install a Ground-Fault Circuit Interrupter (GFCI) outlet near each device and then plug them in just as you would a galley blender?”
Don Casey replies:
You can find galvanic isolators in both the West Marine and Defender Industries catalogs, and I’m sure your favorite chandlery can also get one for you from one of any number of manufacturers.
To answer your second question, ground-fault protection is less of an issue with hard-wired appliances such as a battery charger or a water heater, but you would not be wrong incorporating it into your shore-power wiring. The easiest way to do this is to power these appliances through a GFCI breaker. Although a long wire run could possibly lead to enough capacitive coupling to trip a single GFCI, that probably would not be a problem because of the relatively short distances between outlets on a boat. One GFCI should protect several downstream outlets that are on the same circuit without leading to trip problems.