"But I have a circuit breaker aren't I protected?"


NO....!!!!!!!!!!!


With this old antiquated left over 1938 NEMA L5-30 standard there is approximately 20 times LESS SURFACE CONTACT AREA than there is in a modern SmartPlug, 20X less contact area!!!!!


On boats we are in a corrosive environment, that also MOVES! Add just a little corrosion, some torquing & pulling on the plug and stack all that onto the MINIMAL contact area and we have HEAT.


Heat is generated at points of high resistance in an electrical circuit when pushing current.


PLEASE understand that you can EASILY start a fire with high resistance and NEVER trip a circuit breaker.


As we can see in this photo the wire was not only corroded, due to marine environment and the age, but it also suffered due to the high resistance. The wire jacket itself was melted and then the jacket fractured.