Pump Cable Burns Into Why?

[Leaky Boot]

Find this pretty often. Usually when you get nothing on the Ohm meter you have this. Sometime it looks like it was rubbing on the wall but not really that often. This AM went to a warranty job to see what the problem was on a pump system we installed last summer. Half way down, 100 ft, both red and black wires burned into. No sign of rubbing and we did have well centering devices in place. Was above water level. 12 gauge twist. I am starting to think the cable may have defects. I see no other reason. We spliced it back and worked fine. Amp draw normal.

 

[Valveman]

Wire gets warmer above water than under water. Could have been a bad spot in the insulation where they twist together. Even with centering devices cycling can rub wires together in any location. I have even seen the centering devices rub the wire bare. As fast as they kick that wire out of the plant I am surprised they do as good as they do.

 

[Sponsor]

 

[LLigetfa]

Was there any lightning recently? Could have been a common mode voltage surge carried down the power line from the utility found its way out at a flaw in the insulation. The well casing is almost always a better ground than what the building service has. I have my well casing bonded to the service ground with #6 wire.