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Subject: RE: TWL: major shore power issue
rlchenry@XXX.XXX
Date: Mon Dec 03 2001 - 15:41:25 EST
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Question for the group. Can running too much current
through shore power cause this? I didnt think so, as I
have a 30 amp breaker in the boat. Seems like this
should trip before doing any damage to the plug. It
tripped on me before a few times so I know its
working.
What can cause this? Could it be the boat wiring? Dock
box? Large volume of rain that has occurred in the
last 4 days? ???? !!!!!!
===========================
It is most likely a combination of these things.
The first is yes, you are probably close to or at the rating of the cordset and/or some other "link" in your 120V system.
Second, the rain and/or saltwater causes corrosion at the contacts. This produces a point of high(er) resistance. This higher resistance conducts heat. When the resistance (and the current) get high enough, you can burn, char, or completely melt through the connector legs themselves - often ending in a fire.
This happened to me at my shore power inlet on a previous boat. The wire (for a 30A circuit, mind you) was only 12GA from the factory!!! This caused heat buildup which eventually went toward the weakest point (highest resistance) in my system - a corroded screw terminal on the back of the shore power inlet.
Luckily for me too, the melted contact caused an open circuit before a fire had a chance to start.
Be careful - good connections, corrosion protection, and correct wire sizing ALL THE WAY THROUGH THE SYSTEM!
Best Regards,
Ray Henry
1988 Sundowner 32 Pilothouse Tug
Belhaven, NC
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