Electrical connectors, especially the shore power connectors, on boats are a big source of electrical overheating because the contacts are subject to corrosion and thus increasing the resistance of the connection producing excessive heat. Even without harsh conditions connectors are a troublesome source of dangerous heat from poor contact. (see my previous message: "A Disaster Avoided" concerning a dangerous connection inside Jan's condo)
The way I reduce that source of trouble on my boat is to eliminate the boat/shore-power-line connector. The wiring between the power source selector switch at the ac electrical panel above the chart table,(well inside the boat), begins at the selector switch and terminates still inside the boat near the shore power cord entrance deck plate with three crimped-and-soldered ring terminals. The shore power line, a 50' long three-wire (black 120, red 120, and neutral) #6 SO cord, attaches to the above mentioned three ring terminals with its own crimped-and-soldered ring terminals bolted to the aforementioned ring terminals with short 1/4x20 ss machine screws. Rubber tubing slips over the connections. The shore end of the cable is a "range plug", the sort of connecter used to plug in electric ranges in houses. This system was widely used by the shrimp boats in the area where I built Bandersnatch (Charleston SC) and that range-style receptacle was available at the first two marinas I stayed at. The range plug blades are substantial and I scraped them clean, and sprayed LPS-2 into the female portions, every six months or so. I never had a problem while there were "smokers" at various times with other shore power cords in the marina. My power cord enters the boat through a 2" deck plate on the side of the deckhouse. A rain loop keeps rain from following the cord inside, and duct tape keeps out falling/splashing rain and bugs. I have also seen shore power cords entering boats through cowl or scoop vents. On the other extreme I have actually seen power connections on the topsides (yes, on the outside of the hull below the rail) of some powerboats. For other dock power outlets I made up an assortment of two-foot-long pigtails with a range replicable on one end and whatever was required on the other. I also have a 60' range plug extension cord. While we are at the mercy of the marina standards committee for their side of the connection, I suggest the shore-power-cord be led into the boat through a deck plate or ventilator and the actual electrical connection be made well inside the boat where conditions are dry and clean. It should have it's own circuit breaker, mostly to shut it down quickly in case of trouble. Perhaps the best would be to make the connection inside a fire-insulated breaker box with a smoke alarm above it. You could even use a smoke alarm with a bright light on it, connection the light fed to a relay to short the hot and neutral wires together to trip the shoreside breaker. Remember: since the current flowing through a bad connection is dependent on the loads involved, and such loads will be below the rating of the breakers involved, the breakers will NOT trip to protect you from hot connector dangers. The most ironic boat fire (thankfully inside a steel boat) I know of happened at the Stono Marina in Charleston SC where I lived right after launching. A gentleman had purchased a steel sailboat boat after it had been burnt out and was in the process of rebuilding the interior. It was in the winter and he had just finished varnishing some of his new joinery when he went ashore for morning coffee with his neighbors at the restaurant across the street leaving an electric cube heater going to help the drying process along. Shortly afterwards he noticed a number of fire engines arriving at the marina. Fortunately, steel boats do very well at containing fire. Norm S/V Bandersnatch Lying Julington Creek FL N30 07.68 W081 38.47 > > My first winter aboard, the boat 2 slips down from mine caught fire when > the plug joining an extension cord to a heater or bubbler (I forget > which, it was 6 years ago) wound up underneath a cockpit seat cushion. > Needless to day, I'm already constantly on edge about the risk of fire, > so I really didn't appreciate seeing a subject that I mistook for a > message from my marina while at work. Thank God I don't have a heart > condition. > > Cheers, > Kris _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://liveaboardonline.com/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
