Service Conductor Corrosion

Found this today in the main panel. The service conductors are copper but I was suprised at the level of corrosion and breakdown in the insulation. Any guesses as to the cause or if you have seen something similar before? Thanks!


cause is not important for you to determine. I would recommend that you note corrosion and possible over heating. further evaluation and repair if indicated



Thanks for the link. The condition of the insulation with the cracks and damage concerned me more than just the corrosion on the copper. Thanks for the help!


I agree completely. I was just more interested in any common causes that other folks have seen. The home was vacant and it’s anyone’s guess what was stored in there over the last few decades!

who can tell. that looks like the house on Kimberly. neglect is the word of the day if it is

People rarely do routine maintenance on electrical equipment. The conductors need to be removed and cleaned. I would apply an oxide inhibitor. The lugs then need to be properly torqued.

What you are seeing is loose connections at the lugs. The wires are over heating which is causing the copper to turn black and green and the insulation to crack.Write it up for evaluation and repair by a licensed electrician.

I don’t think so.

Well Roy, I have been an electrician for 38 years in industry and residential. I have seen what your seeing many times. The lack of oxidizer may have been the beginning of the issue as copper and aluminum don’t get along together well. Once the two materials start to interact with no oxidizer, gaps and arcing and overeating starts to occur and what you see is the end results. Its not good no matter what.

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Have you ever been incorrect?

I never said I was perfect, nobody is, but I know what I know. Don’t want to step on any ones toes. You asked for responses and I’m just responding.

I have to defend Terry in this case. I recognize this panel. I have inspected this property and there is overheating and the lugs do need to be tightened.

Thank you Paul,appreciate your support.