Marinco Reverse 30A to 50A "Y" Adapter Product Features Provides a boat with 50A 125/250V power from two 30A/125V locking receptacles. The Reverse "Y" Adapter (167RYN) 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. The reverse "Y" provides 50A 125/250V power when only 30A 125V receptacles are available. Note: Reverse "Y" will NOT work with 50A, 125V, 3-wire inlets. Power is provided in both circuits to the 4-wire inlet, but the dockside receptacles limit the current in each circuit to 30A. The two 30A 125V receptacles must be supplied from a single power source providing from 208V to 250V between them for proper operation.