Where must the grounding conductor of the galvanic isolator be connected?

The grounding conductor of the galvanic isolator must be connected to the boat's AC grounding system. This connection is essential because the galvanic isolator is designed to prevent stray currents from causing corrosion on underwater metals while still allowing necessary ground fault protection for the AC electrical system. By connecting it to the AC grounding system, the isolator ensures that electrical faults in the system can safely return to ground without creating a path through the water, which could lead to corrosion issues or electric shock hazards.

Additionally, galvanic isolators function by allowing unidirectional current flow to prevent galvanic corrosion, which typically occurs when different metals in contact with water create an electrochemical reaction. Properly connecting it to the AC grounding system is crucial for effective operation, ensuring that the vessel remains protected while still maintaining safety protocols for the electrical system.

The other options do not provide the necessary context for grounding or fault protection in marine electrical systems. Connecting to the battery terminal or the onboard generator does not facilitate proper grounding of the AC systems and may not provide the protection intended by the galvanic isolator. Furthermore, connecting to the DC power supply would not be effective, as the galvanic isolator's primary function is related to AC currents rather than DC. Therefore, the