Black Ground wires

[mnahrgang (Mark Nahrgang, C.R.I.)]

Got a new one for me today… 60 year old home with a newer Square D 200 Amp panel/service. NM Romex, and cloth covered copper wiring. No signs of fire or scorching, but all of the grounding (and grounded) conductors had a black coating on them. When I first looked at it, I thought it was aluminum, then tin coated, then I noticed they all had it. Is this a concern? What would you say if anything?

[mlarson (Michael Larson, WI Lic. # 1672-106)]

@mnahrgang

Got a new one for me today… 60 year old home with a newer Square D 200 Amp panel/service. NM Romex, and cloth covered copper wiring. No signs of fire or scorching, but all of the grounding (and grounded) conductors had a black coating on them. When I first looked at it, I thought it was aluminum, then tin coated, then I noticed they all had it. Is this a concern? What would you say if anything?

Its oxidation and can be a sign of exposure to sulfur compounds including those in Chinese Drywall.

It can also occur in high moisture environment.

[mnahrgang (Mark Nahrgang, C.R.I.)]

@mlarson

Its oxidation and can be a sign of exposure to sulfur compounds including those in Chinese Drywall.

It can also occur in high moisture environment.

Ok… there you go. Wet basement.

[bwiley (Blaine Wiley)]

I saw it today. In this case it was Chinese Drywall.