I recently came across a posting that is a good reminder for all of us. It was a standard 30-amp shore power cord. On the outside, there was slight evidence of heat. Upon taking the plug apart, it’s completely melted. It’s not my picture so I’ll not post it here but you can see it at: http://www.baylinerownersclub.org/forum/showthread.php?t=13761. Also on that thread is a posting by a Harbormaster showing one that completely failed and burned.
When flowing through a corroded connection, even considerably less than 30 amps will produce a dangerous amount of heat. Corrosion brings resistance and resistance brings heat. One good technique to efficiently chase these problems down is to use a small infrared heat sensor. When you are running an electrical load, check for warming at the connectors and in the wiring within the boat to the main breaker panel. A good electrical load is an electric space heater. Where there is heat there is resistance, and you want to catch it before it becomes a fire risk.
I use a Fluke 561, pictured below. This one runs around $150, but I’ve seen IR temperature sensors as low as $35. And, of course, you can feel for warmth as well. I use the IR temp sensor for so many different purposes that I wouldn’t dream of doing without it at this point.
Check out the pictures referenced above and remember to check your cables and connections a couple of times a year. Replace them when there is any evidence of corrosion, browning, or heat.
James Hamilton, email@example.com