Black Ground Wires ????????????????

[a.wayne3@verizon.net]

Really strange one......Earlier today the inspector nextells me to ask me to come to this house he is doing a final on.So I went there and he has the meter can front off looking inside.Whats there,the #4 ground wire is almost black , the white from the arrestor is brownish.
All else seems to be normal.Next we go to the panel,everything besides the ground wires are normal ,but all of the ground wires are black for at least 6 to 8 inches from the ground bar up towards the connector.This is a back to back service and neutrals are mixed with the grounds on this bar,some grounds are double lugged all neutrals are individualy lugged.the change of color is only on the ground wires none of the neutrals have changed color except for the exposed areas that are making the connections.
I am thinking a nearby lightning strike traveled through the footer bond and into the meter thru the ground wire and into the panels ground bar,and this has caused the change of color in the bare copper.As a precaution i replaced the arrestor and put power to the house all checked out fine.Now the inspector says he will pass but not release the house until he gets a letter from our company saying that we tested the electrical system and found it to be intact.Any thoughts ????

 

[david]

Re: Black Ground Wires ????????????????

Not really, though I inspected a service once. After it was energized the neutral started to over heat. I did not catch that the electrician cross-threaded the service neutral lug. The neutral lug felt tight but because the lug was crossed threaded it never tightened.

He was an very experinced electrician and this happened to be his fathers house.

Recheck all your connections

 

[bphgravity]

Re: Black Ground Wires ????????????????

If absolutely no other problems are found to exist, it sounds to me as if this is a manufacturing issue.

Copper does change colors in certain environments and I have had the occasional roll that has a darker than normal color to the copper itself. it would be only near the connections and terminals does seem a little odd.

Add in the arrestor condition and I think ligntning or some other type of surge may have been prsent at some point on the grounding system. Lightning does some weird things!

 

[bennie]

Re: Black Ground Wires ????????????????

Check the ground at the distribution transformer.

Is there other houses on the transformer?

 

[mikeames]

Re: Black Ground Wires ????????????????

If it were energized, could there have been any toxic fumes around the panel? Could the charge on the conductors accelerated the oxidation rate in the presence of paints or chemicals??? I dont know???

 

[tom baker]

Re: Black Ground Wires ????????????????

Try sending an email to the copper development association with your question.