This adapter allows for safe use of a 50 amp onboard power system, and your 50A shore power cord, at docks where only 30 amp power is available. The reverse "Y" adapter has two male plugs with special power isolation circuitry for added safety. When one plug is connected to a receptacle, the circuitry isolates the second plug.

Provides 50A 125/250V power when only 30A 125V receptacles are available
Will NOT work with 125V 3-wire inlets; your power inlet must be a 4-wire, 125/250V inlet
Power is provided in both circuits to the 4-wire inlet, but the dockside receptacles limit the current in each circuit to 30 amps; this will still allow you to use most of your appliances
Both dockside reptacles must be supplied from the same power source (this is the norm), and provide 208V to 250V between them
This adapter is equipped with a cover and sealing collar system (SCS), and is suitable for use in wet locations