Beschrijving
Internally, the galvanic isolator consists of two diodes connected antiparallel. Diodes pass voltage in both directions in this circuit, but only above a certain threshold voltage.
The voltage, at which a diode will conduct, is about 1.4 Vdc. The isolator is placed directly behind your boat's 230V connection. This forward voltage of the galvanic isolator is higher than the potential difference between metals. As a result, this voltage will not be able to cause conduction and the galvanic isolator will therefore prevent an electrolytic current from forming. However, if there is a (higher) fault voltage in the AC circuit, the diodes will allow the current to pass through and the earth leakage switch will break the circuit.
The advantage of the galvanic isolator is its limited weight, price and size. The disadvantage, however, is that it requires a good shore ground connection. The second phenomenon is that electrolytic corrosion can occur not only through the earth connection, but also through the neutral conductor (if this has an on-board connection to earth at a consumer by means of a suppression filter or the like). An alternative to the galvanic isolator is the isolation transformer which, however, has a higher purchase price.
