Victron Energy Galvanic isolator VDI-16

Galvanic isolator VDI-16, VDI-32, and VDI-64

The galvanic isolator prevents electrolytic corrosion. It blocks low-voltage direct currents that enter your boat through the shore power ground cable. These currents can cause corrosion on the metal parts of the boat underwater, such as the hull, propeller, shaft, and so on.

The galvanic isolator internally consists of two diodes connected in an anti-parallel manner. This connection allows the diodes to enable current to flow in both directions, but only when a certain voltage threshold is exceeded. The voltage at which the diodes conduct is 1.4 V DC.

The isolator is installed directly behind the 230 V connection of your boat. The forward voltage of the galvanic isolator is higher than the potential difference between metals. As a result, the voltage does not allow a current to pass, and the galvanic isolator thus prevents any electrolytic current. However, if a (higher) fault current occurs in the AC circuit, the diodes allow the current to pass, and the residual current device interrupts the circuit.