SHORTCUT, NOT CIRCUIT
Here, you see a ProMariner Galvanic isolator installed in such a way that it is unable to do its job. Any boat that is plugged into shore power for extended periods of time should have a galvanic isolator installed. But it needs to be wired correctly if it is to function as intended. The unit should be installed in series with the green grounding wire in the shore-power circuit. That means two studs on the isolator. One in from the shore and one out of the isolator to the boat’s air-conditioning distribution panel. The photo shows that the installer put both the “in” and the “out” conductors on one stud. This effectively eliminates the isolator from the circuit, rendering it useless as installed.