Safely powers 50 amp 125/250 volt boat from (2) 30 amp 125 volt receptacles at dockside. 4-pole contactor breaks both hots and both neutrals to prevent possible "live" plug when not engaged. UV resistant housing, 30 amp plug that connects to 30 amp shore power, safety indicator light, internal cord clamps, sealing grommets, anti-fog-rain-humidity environmental seal, 50 amp connector body that mates with boat cordset and Hubbell connector and plugs. Shuts off power if improper wiring condition exists on power center or if 1 plug is not fully engaged. Senses polarity of 30 amp receptacle on dock and (2) 30 amp receptacles from opposite phases.