Galvanic Isolator VDI-16A, 16 AMP Max Waterproof PottedThe galvanic isolator prevents electrolytic corrosion. It blocks low-voltage DC currents that enter your boat via the shore power earth wire. These currents can cause corrosion to the boat&&';;s underwater metals, like the hull, propeller, shaft, and so on.The galvanic isolator consists internally of two diodes which are connected in an 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 120V - 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.Please contact your dealer for any returns, repairs or support issues related to this product. Owner&';s Manual (pdf)