Looking at the photo above which is showing the terminal on a shore power neutral conductor that has gotten a bit too warm reminded me of a question posed to me earlier this at the IBEX show in Louisville. One of my ABYC certified technicians asked me why it seemed that it was almost always the neutral conductor that got burned or melted when there was a problem with shore power. The answer is not simple. Now, in the above photo, the cause of the heat could have been simply a loose screw holding the terminal to the lug, but the more complex answer has to do with what we know as harmonics. Harmonic distortion has become more mainstream with the increased use of what we know as non-linear electrical loads. Think computers here as a great example of a non-linear load. A modern boat is loaded with non-linear loads. The explanation can be found here:
Check it out and you’ll have a better understanding of this emerging phenomena.