Plugging For Safety

Two new shorepower cords designed to reduce the risk of electrical fires at the inlet.

By Charles Fort

Photo of SmartPlug shorepower cordPhoto: SmartPlug

As Seaworthy readers know, 55 percent of fires on boats originate in the electrical system, with the shorepower inlet being one major source of fires in the 120-volt AC system. Fires often start at the inlet connection because of corrosion or damage to the metal connector blades. Once blades begin to corrode, there is less contact area for current to flow, which causes heat buildup. Arcing also damages the blades when a connector is disconnected under load and electricity leaps from the connector to the tip as the plug is removed. Eventually, the heat from arcing and corrosion can melt insulation and cause a short in the wiring, which can ignite anything flammable nearby. Seaworthy has always recommended cleaning the connectors and avoiding making connections with shore power on. But in the past few years, new shorepower cord designs have been introduced that have the potential to reduce the number of fires originating at the inlet.

Marinco EEL

EEL stands for Easily Engaged Lock and has a new clamp-type locking mechanism instead of the old-style locking ring. Marinco says it creates a watertight seal, which should keep corrosion at bay. The EEL also has LEDs on both ends to show that power is flowing, which will hopefully remind you to turn off the power before disconnecting, eliminating arcing. The EEL comes with a cord light at the boat inlet side, which acts like a flashlight, making it easier to find the inlet at night. But since Seaworthy still recommends turning the power off before connecting the cord, the light won't be very useful. The EEL system meets UL safety standards and costs about $100 for a 50-foot cord.

SmartPlug

The SmartPlug inlet and connector kit, designed to replace the current AC inlet on your boat and the connector that plugs into it, has straight, rather than curved blades, which have more contact area and make it easier to plug in. There's no danger of damaging the blades while you're trying to twist them in on a dark night. The cord connection is weatherproofed with two separate seals to keep out moisture and salt air, and it securely snaps into place so you know when you're connected. Finally, a thermal cutoff shuts off the power if it senses a temperature over 200°F and restores it when it has cooled.

The challenge, of course, is the need to replace your boat's shorepower inlet. SmartPlug Systems says its inlet can be installed in about 30 minutes. For a 30-amp service, you can buy the inlet and the connector end and refit your existing cord for about $225, or you can buy the complete cordset and the inlet for about $300. Fifty-amp connectors are also available for a bit more. Eventually, SmartPlug plans to have inlets and connectors for the dock pedestal, too, though the installation for that is not for the do-it-yourselfer and must be performed by a qualified electrician. The SmartPlug does have one potential safety issue: If the thermal cutoff trips and the power goes out, anyone working on the AC system might get a nasty surprise when the thermal cutoff restores the power. The SmartPlug is not UL listed, but has been tested to recognized standards by another independent facility (ETL).

While neither of these solutions is perfect, they both offer the promise of reducing fires due to shorepower cords and extending the longevity of the connectors and inlets. We'll keep you posted as we get real-world data through our claim files, and we'll let you know as other products come to the market. 

For more on how shorepower cords cause fires, see When Your Shorepower Loses Its Cool at: www.BoatUS.com/Seaworthy/magazine/SeaJul10.pdf

— Published: January 2015

 

Seaworthy, the damage-avoidance newsletter, is brought to you by the BoatUS Marine Insurance Program. For an insurance quote, please call 1-800-283-2883 or apply online at BoatUS.com.

 

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