Marinco Dockside 30A to 15A Adapter with Ground Fault Protection. If you use an AC drill, buffer, grinder or other power tool around your dock, this adapter will help protect you. Provides a safer hook-up to 30A dockside power for up to three attached tools, and provides protection against potentially lethal electric shock. GFCI (Ground Fault Circuit Interruptor) trips at 4–6mA. Total load of attached tools must not exceed 15A. Rated corrosion-resistant and rainproof for outdoor use. Five-year warranty.