A while back I had a problem with my shorepower cord and it had an area, which looked like it was hot. At the time the inlet receptacle didn't show any signs of overheating so I bent the prongs slightly so as to provide more pressure on the connector chord and make a better contact. About three days later I was checking on the boat and for some reason decided to check the inlet and the plug and noted the darkened area. The shorepower inlet was removed and an obvious hot spot noted on the outside of the inlet. One of the conductors had a loose setscrew which was the apparent cause of the problem. The shield surrounding the inlet did not have any visible signs of damage on the outside. It was noted that the distance from where the three-conductor wire enters the inlet to the next point where it is secured from movement was *at least* two feet. There was neither sealant around the terminal nor any "Loctite" type material on the setscrew to prevent the screw from loosening, if in fact it did become loose. The conductors were marine-grade and tin-plated. There are several possible causes, that I can think of, of the set screw loosening: (1) temperature expansion and contraction, (2) not being tightened enough to begin with, (3) vibration of the wire from the diesel engine, (4) loosening of the stranded wires under the set screw. There may be other possible loosening mechanisms. The moral of this story is if you see something that looks like it melted look further and see if you can find out why. I'm certain that diesel engines cause vibration of everything on board and wires are no exception. My feeling is vibration was either the cause or a major contributor to this problem. Wires/conductors should have support close to the terminus.
