Wires turning black in panel

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Exceptional

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Oxford, FL USA
We are an electrical contractor in Florida. Have three homes on the same block that wires have become black in the panel
We have had the power company out and it is not from their work.
The homeowners are concerned and want an answer to this issue
Thank you for any suggestions!
 
Any sign of overheating, or is the blackening perhaps a chemical change?

Loose (improperly torqued or worse) connections are the most common cause of wires overheating near where they terminate.
 
GoldDigger said:
perhaps a chemical change?
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I was thinking the same way. Are there any conduits from these panels that end up in a pool equipment area? I have seen this in rooms with chlorine.

Roger
 
Exceptional said:
We are an electrical contractor in Florida. Have three homes on the same block that wires have become black in the panel
We have had the power company out and it is not from their work.
The homeowners are concerned and want an answer to this issue
Thank you for any suggestions!
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The conductors or the insulation?
 
Besoeker said:
The conductors or the insulation?
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That was my question as well, one of them anyway. That would help us understand whether we are dealing with an overheating issue. However, my first question would have been, what were those homeowners doing in the panel anyways? In other words, why did they discover this condition, and could it be that other homes have it too and just don't know it yet?

 
Exceptional said:
We are an electrical contractor in Florida. Have three homes on the same block that wires have become black in the panel
We have had the power company out and it is not from their work.
The homeowners are concerned and want an answer to this issue
Thank you for any suggestions!
Click to expand...

Are stating that the copper conductor itself is turning black? Insulations are often black, red, and white in addition to any none insulated EGC.

But, this is what I discovered after a brief search:
Copper oxidizes slowly in air, corroding to produce a brown or green patina. At higher temperatures the process is much faster and produces mainly black copper oxide.

And Chinese dryway may be a contributing factor as was pointed out. It would be a good thing if you inspect other other places if the home also for the same oxidation issues, outlets, switches, etc.
 
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Exceptional said:
We are an electrical contractor in Florida. Have three homes on the same block that wires have become black in the panel.
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Says in your profile that you are on code cycle 2013 and that was an unlucky year for codes.


Since most of the insulation on the conductors is already black (except for the neutrals) I will assume that you are talking about the exposed copper turning black.

Where are these panels located? Basement, Garage, exterior wall? If there are enough chemicals to turn copper black there may be a bigger problem.
 
Blackening conductors in new homes with a common builder, I agree the.cause is likely sheetrock offgassing sulfur.

See a lot of conductor discoloration in mills and WWTP where there is unusual H2S or sulfur dioxide exposure.
 
charlie b said:
That was my question as well, one of them anyway. That would help us understand whether we are dealing with an overheating issue. However, my first question would have been, what were those homeowners doing in the panel anyways? In other words, why did they discover this condition, and could it be that other homes have it too and just don't know it yet?
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X2. A tale of discolored insulation in panelboard combined with lack of specificity concerning discovery, odors etc., seems odd.
 
charlie b said:
what were those homeowners doing in the panel anyways?

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Respectfully, When did it become illegal for a homeowner to remove his/her panel cover? If the home owner was installing a receptacle, a circuit, anything… does it matter..?

chemical reaction, interesting post..
 
ritelec said:
Respectfully, When did it become illegal for a homeowner to remove his/her panel cover? If the home owner was installing a receptacle, a circuit, anything… does it matter..?

chemical reaction, interesting post..
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It isn't illegal-the big question is that how did they know a problem existed-what were the circumstances surrounding discovery of discolored conductors? Any little bit of extra info might be helpful.
 
Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.Chinese drywall.
 
Exceptional said:
We are an electrical contractor in Florida. Have three homes on the same block that wires have become black in the panel
We have had the power company out and it is not from their work.
The homeowners are concerned and want an answer to this issue
Thank you for any suggestions!
Click to expand...

is *all* the copper in the house discoloring? yes?

Chinese drywall.
 
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