Black film on copper wiring in main panel

Need a quick answer. I don’t suspect Chinese drywall. Is there another reason for copper to be black like this?
Can’t seem to figure out how to put a picture from my phone in. On some of the neutrals it looked almost crusted on.

Sulfer, chemical compounds and high moisture environments are possibilities.

Check copper pipes and HVAC compnents

The copper pipes looked ok. That’s why I don’t think it would be the drywall.

Heres a couple of pictures.



I have not heard of any bad dry wall in Canada.

Chorine ,cat pee, Horse Pee and or other chemicals could be the reason .

Second floor condo. The panel is about eight feet from the laundry. Rh was 35%. I even ran the washer through a full load to re check RH. only went up 3%. I’m stummped.

bet Javex is the cause ( Chorine )
They say do not store laundry supplies near your furnace for that reason

Could be

I would suspect the chlorine in the air from the laundry. This is a form of oxidation and I have seen this exact condition on wire terminations many times where chlorine and moisture are both present.

Best to recommend service by a licensed electrical contractor. Normally it is a process of cleaning the strands with a wire brush, applying an anti oxidant compound, and properly torquing the connection.

The source of moisture may be the dryer instead of the washer. I would suspect ventilation/air flow might not be adequate in the area where the panel and laundry is located.

I inspected a home a few years back that had the pool equipement along with its chemical (chlorine) stored in basement, basement had a walk-out to the pool, and the electrical panels were located in that same room.

Copper wiring were not discoloured but cabinets were rusted.

I can fully believe that. I think in many instances either the ambient air temperature, or the lack of adequate ventilation, or both, are contributing factors. I would assume in the basement you inspected, the temperature or RH might have been more moderate than in the 2nd floor of the condo, especially with laundry equipment in close proximity.

On a side bar, I have also repaired the same oxidized wire terminations in electrical cabinets that control industrial plastic extrusion processes. RH is typically very high and this is very common in processing systems for PVC products.

I guess there are so many possible variables in the world that it is difficult to speak in terms of absolutes or certainties.

I wrote it up as follows:
It appears that the copper wiring in the service panel has oxidized. The exact reason is unknown as there are many variables as to why this can happen. It is recommended that a licensed electrician evaluate and repair as required.

I agree, I’ve seen residual sulfer corrosion/damage/deterioration/staining like this multiple times. Was there any other blackened areas/components like Michael said?

I’m leaning to the dryer vent causing this issue (blackened copper electrical wires and water pipes) at yesterdays inspection. Service panel was 10’ to left of dryer. Home built in the 60’s. Sorry for blurry photos of water pipes.

Rodent urine. I think you where on to it in yourfirst post Roy.
Any dropping in or around the panel?

Just a question for anyone and everyone, when you theorize the dryer and chlorine are the culprits are you thinking excessive chlorine in the water or excessive bleach use combined with a leak in the dryer exhaust pumping this chlorine laden humidity into the somewhat isolated room?

Just trying to get my brain wrapped around the mechanics of it.

Any theory?

Dried out trap nearby? Any other way for sewer gasses to get into the area?