T&T: Hot shore power connections

[Peter Bennett]

Tuesday, March 25, 2008, 3:01:21 PM, Scott wrote:

SEB> Thanks to everyone advising immediate replacement of my shore power cords.
SEB> I was able to find new cord ends and receptacles here in Los Suenos (well
SEB> nearby anyway) and they are now all brand new and sparkling clean.  

SEB> Two days ago I started to watch the connectors every hour or so. I kept
SEB> feeling them to see if they were HOT.  Well they were warm, but not HOT.
SEB> Imagine my horror when I disconnected them yesterday morning and found the
SEB> neutral had completely melted and was floating freely in goo.  Even though I
SEB> was putting my hand on the parts every few hours it was melting right in
SEB> front of my eyes and I didn't know it.  There were no indications in the
SEB> boat or at the shore power circuit breaker.  Amazing, as I would have
SEB> thought the breaker would trip?

According to your description, you had a high resistance connection in
the neutral conductor, causing the connector contacts to overheat -
this would probably have reduced the current drawn through the
breaker, so there would be no reason for the breaker to trip. It would
also have resulted in a lower-than-normal voltage on-board.

A breaker will only trip if excess current is drawn through it -
either by running too many high current loads, or if there is a fault
resulting in an unwanted current path from hot to neutral or ground.

SEB>  The net of this for me is WARM is BAD.  It
SEB> doesn't have to be HOT to be bad!  Also, ANY signs of burning will be
SEB> addressed immediately by me in the future!  Anything less then bright silver
SEB> contacts will be unacceptable.

SEB> Anyway, as I said I was able to replace everything and I'm better than new!
SEB> Thanks to everyone who provided advice on the topic.  

SEB> Scott Bulger, Alanui, N40II, Seattle WA
SEB> Leaving Los Suenos in the morning!


-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca