Coastal electricity blocks the low voltage accurate current entering your boat from the grounding cable. These currents can create corrosion in the water contact with water, such as the body, propeller and shaft under the boat. It consists of two diodes. When connected in this way, the diodes allow bidirectional current only above a particular limit voltage. The voltage transmitted by the diodes is approximately 1.4 VDC. Advanced voltage from the galvanic insulator is more than the potential difference between metals. As a result, voltage does not allow transmission and thus the galvanic insulator prevents any electrolyte current. However, if there is an error voltage (higher) in the AC circuit, the diodes allow the current to pass and the illegal current relay cuts the circuit.