The galvanic isolator prevents electrolytic corrosion by blocking low-voltage DC currents that enter your boat when connected to shore power. These currents can cause corrosion to the boat’s hull, propeller, shaft, and so on.
Victron galvanic isolators consist of two diodes that are connected in anti-parallel fashion. When connected in this way, the diodes allow current in both directions but only above a certain threshold voltage. The voltage at which diodes conduct is about 1.4 Vdc.
The isolator is installed directly behind your boat's 230V connection. The forward voltage from the galvanic isolator is higher than the potential difference between metals. As a result, this voltage will not allow conduction, and as such, the galvanic isolator will prevent any electrolytic current. However, if there is a (higher) error voltage in the AC circuit, the diodes will allow current through, and the residual-current device will break the circuit. Available in VDI-16, VDI-32 and VDI-64 models.