Holy Cow !
I hope at the minimum tic’ed it.
Something ain’t right here.
The plastic should be pouring out of the panel.
The melting point for average, commercial, low-density polyethylene is typically 221 to 239 °F. That plastic was nearing the Flash point!
http://www.tcforensic.com.au/docs/article10.html#2.1.2
If your great minds have not conduced…
“This panel should not have ever been opened”.
Not that a reduced competition would not help…
David you ain’t no good!
No Kidding.
Some cowboys don’t get it.
I did. Not the smartest thing I’ve done but I won’t do it again. Didn’t put my thermometer on it until after I saw the melted plastic… I was “shocked” to see the actual temp :shock:
LOL! Good one! 
Checking the panel to see if it is hot in both ways should always be done before desiding on whether or not it should be opened.
Home Inspector 101 and I bet many don’t or just forgot how important this is.
Great post to learn from and thanks to David for the reminder.
Luckily, the black panelboard and breaker plastic is not LDPE, but polyamide reinforced with mineral fibers – a class of materials that doesnt’t melt, in certain formulations, up to 650 degrees Fahrenheit. I would imagine, the flash point there is even higher.