The galvanic isolator consists internally of two diodes which are connected in anti-parallel fashion. When they are 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.
Brand

Victron Energy

Peak Current (20 ms) 6000 A

Maximum Current 64 A

Connection M6

IP Rating IP67

Dimensions H63 x W164 x D335mm

Weight (kg) 3.2

Warranty 5 Years

Country of Manufacture Netherlands

NOTE that a Isolation Transformer IS MUCH MUCH better unit than a Galvanic Isolator as they give you a 100% power isolation from any other outside DC power transfer. however so is there a cost difference.