2007 Mazda5 TS2 1.8 petrol

I had a four way, a 12v car fridge and a 12v car WiFi generator plugged into the rear power socket for a 200 mile journey.

At the end of the journey everything was still working including the socket BUT the male plug on the 4 way had partially melted into a crumpled mess of misshapen plastic.

Why did it get hot enough to melt? Is it a fire risk? Why is the current so powerful in that socket?

Has this happened to anyone else?

 

Poor contact causing high resistance resulting in excessive heat.

 

ive bought a new 4 way and sort of velcroed it into the socket so it’s jammed in, hopefully that will avoid it working loose and maintain good contact