Excerpt from Instruction manual
The DEI Marine Galvanic Isolator (GI) is a fail-safe, solid-state DC isolation/ AC coupling device for marine applications with exceptional product performance and certifications to ABYC A-28. Galvanic isolators are desirable whenever a boat is connected to AC shore power, due to a galvanic circuit, which can cause corrosion of the boat and its drive system components. Due to the difference in the potential of the hull and drive system metals compared with the shore grounding system or other boats, a galvanic current, which causes corrosion, can flow. A galvanic isolator is installed in series with the shore power cable grounding conductor to prevent the flow of galvanic current thereby preventing galvanic corrosion.
Per ABYC A-28, the DEI Marine model GI family has a DC blocking voltage of at least 1V. At a voltage below this value, the GI blocks the flow of DC current and allows AC current to pass. At voltages above the blocking voltage, such as could occur from an AC fault or lightning, the GI is a bi-directional conduction device that readily allows all current to flow, thereby safely limiting the voltage on the boat.
DEI Marine Galvanic Isolators are strictly current rated and can be used on any voltage class system. Since A-28 requires a system voltage rating on the nameplate, all DEI Marine Galvanic Isolators are name-plated for use on systems of 600Vac or less.
DC Leakage Current
For a given DC voltage across the GI, there will be a small DC leakage current. This value will be negligible (less than 1mA) at the worst-case galvanic voltage difference anticipated across the device, and well below the limits in ABYC A-28. The leakage current is a corrosion-causing current that is minimized with the DEI Marine design.
Steady-State AC Current
Galvanic isolator models are rated to carry the steady state AC current for which the shore power cable is rated. The ratings offered by DEI Marine are 30A (which has been certified and nameplated for 35A continuous to satisfy European requirements for a 32A rating), 50/60A (for a single 50A shore cord or two 30A shore cords), 100A (for a single 100A shore cord or two 50A shore cords), and 200A (for a single 200A shore cord or two 100A shore cords).