Shore Power

Stick to approved marine shore powercords  with female twist-lock fittings that match male sealed receptacles on the boat, and male fittings for the female receptacles on the dock. Several plug patterns are in use for specific purposes, and it is essential that the correct plug be used in the receptacle. The specially made cords are sealed from moisture and rated for the correct voltage and amperage. It’s better to use factory made adapters, if plugs don’t fit receptacles, than to try to cobble something together that’s not made for the purpose. Extension cords modified to fit the receptacles can cause shock or fire. The shore power system is grounded at the dock junction box, but the breaker protects only the dock wiring, not the circuits inside the boat. Power cords don’t last forever and should be inspected periodically. Look for chafes and cracks. If plugs are corroded they may arc, and if they are burned, they have overheated in the past and could cause shock or fire, so they should be replaced. If a shore power cord in use feels more than slightly warm, there is resistance somewhere and the cord should be repaired or replaced. Boat harbors have a lot of problems due to owners using incorrect cords, incorrect plugs, plugs that are burned or corroded, plugs that are forced in or not inserted correctly and locked, and with pedestal boxes that have been altered by boat owners. All of these situations can be dangerous. Any time you plug in to an unfamiliar dock box, check it first with a pocket polarity tester and with a voltmeter, then ascertain that the plug fits snugly and securely into the receptacle.