It probably wasn't a short. You had a poor connection that resulted in a lot of heat even though there wasn't enough current to trip the breaker. This is one of the reasons connections need to be made in boxes.

That might make sense. However, theres metal on the yolk and it too was melted a bit where I presume the wire was pressing up against.

So there was a metal on metal contact. I figured that would have been an automatic dead short.

So with the hot wire melted to half its size (about a 1/8-1/4 of inch of it)... I would guess that would have failed immediately with the fridge compressor kicking on, or do you think that weakened portion could work for an extended period of time before totally breaking?

Just trying to rationalize if this just occured or happened a long time ago.

Flawed logic. A toaster gets red hot but does not trip the breaker. Welders generate 6000 degrees and some of them operate on 120 volt 20 amp circuits. Melting heat can be created without tripping breakers.

By the way, the thing holding the receptacle in place is a YOKE. Yolk is the center of the egg.

In addition to connections must be made in boxes, AFCIs also address the issue that certain wiring failures can cause a fire without exceeding the circuit ampacity.

This post was edited by ronnatalie on Sun, Oct 13, 13 at 9:20