there looks to be some corresion and heat damage. Was this cable used on a 20 amp breaker with a devices that draws over ten amps? Ever exposed to water?
It appears to be that this was exposed to water. I have not actually shorted a line with water, but I have seen the damage at a science museum. It appears not as melted, but sort of scraped or chipped, wich is what I see. That explains the corrosion, right?
Water, uless exposed to constntly moving water (like in a river), does not have a corroding effect on plastic, or anything else for that matter. It is pH neutral.
LOL - yes and I'll be interested to see if you can work out how I managed to melt the neutral. The lead it was on was fine and the damage was confined to the cable in the socket.
The answer can be found in the other posts within part B and one of the earlier QOTD posts.