Wednesday, November 24, 2010

Shore power plugs

One of our suppliers passed on this article (picture below) that was published in Latitude 38 magazine.
I found it interesting and wanted to post it here for others to read.
As a marine surveyor I often go to a meticulously cared for vessel to perform a survey and find the ends of the shore power cord to be badly worn and in need of replacement.  It amazes me how something that gets handled every time the vessel leaves the dock can be left to deteriorate to the point where it causes so much resistance that it causes a melt down or in the extreme case in the article, almost kills someone.
If your plug is worn it would serve you well to replace it. I have seen insurance claims denied for fire damage caused by faulty receptacle plugs, it is often considered a maintenance issue and as such is not covered.
When unplugging the shore power cord from the vessel turn off the main circuit breaker on the vessels electrical panel before unplugging the vessel. Ideally this should be done on the dockside panel but they are often locked or otherwise inaccessible. When the plug is disconnected while energized it creates little arcs that cause minute pitting on the connectors. The pits fill with carbon deposits that are created when it arcs, the carbon creates resistance that leads to more arcing, more pitting, more carbon, etc. Before to long you have created significant resistance in the connection and are well on the way to a melt down.

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