# Blackened conductors in receptacle boxes



## backstay (Feb 3, 2011)

Not soot, that’s corrosion. Are they outside walls? If they are then it could be moisture from air infiltration. The only other place I see it like that is in lift stations(sewer gas).


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## Sparkied (Jan 2, 2018)

backstay said:


> Not soot, that’s corrosion. Are they outside walls? If they are then it could be moisture from air infiltration. The only other place I see it like that is in lift stations(sewer gas).


Some were on inside walls aswell, and in switch boxes on inside walls


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## backstay (Feb 3, 2011)

That’s not aluminum wire is it?


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## Sparkied (Jan 2, 2018)

backstay said:


> That’s not aluminum wire is it?


All copper conductor, under the insulation its perfectly shiny, checked the inside of the panel and its normal, no discolouration


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## backstay (Feb 3, 2011)

I’d say high moisture.


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## Majewski (Jan 8, 2016)

its possibly that chitty asian drywall that was going around that changes copper like this


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## Jlarson (Jun 28, 2009)

Looks like hydrogen sulfide effects.

House got rocked with some of that chinese drywall?


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## splatz (May 23, 2015)

Soot wouldn't selectively cling to the copper like that. If the house was built in 89 that wouldn't be the funky Chinese drywall but it also wouldn't affect just one room. Maybe this room for some reason was gutted and re-drywalled in the bad Chinese drywall years. Maybe there was something stored in there for a period. Maybe something was coming up from the basement or down from above through a floor register. A lot can happen in 33 years.


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## frankendodge (Oct 25, 2019)

Corrosion/oxidation for sure. Thats what copper plumbing looks like after being hung with bent framing nails instead of copper or plastic straps. The galvanizing on the back of that box looks like its lifting as well. Could be drafts, even on inside walls if cold air can leak around holes in the top plate. Or the opposite. Air tight houses with high efficiency furnaces and no air exchange can cause all sorts of moisture issues. That house should have sealed unit windows, do they fog fog up?
Where in Ontario?


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## Almost Retired (Sep 14, 2021)

I agree with @Jlarson that is probably hydrogen sulfide. I work in a town about a hundred yards from a paper mill. Every bit of copper you can find that gets outside air is black and crusty. the white stuff on the wire insulation is the galvanize/anodize corroding off of the metal box


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## frankendodge (Oct 25, 2019)

Never worked around H2S before.. very interesting that it can do this. I want to know more.
I would wonder why it is only affecting certain devices though.


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## Sparkied (Jan 2, 2018)

frankendodge said:


> Corrosion/oxidation for sure. Thats what copper plumbing looks like after being hung with bent framing nails instead of copper or plastic straps. The galvanizing on the back of that box looks like its lifting as well. Could be drafts, even on inside walls if cold air can leak around holes in the top plate. Or the opposite. Air tight houses with high efficiency furnaces and no air exchange can cause all sorts of moisture issues. That house should have sealed unit windows, do they fog fog up?
> Where in Ontario?


This is exactly what i was thinking, the home is air tight we live in northwestern ontario. Maybe there are drafts everytime a door is open to equalize the pressure in the home it comes straight through the top plate holes or maybe the vapor barrier around some of the outside boxes arent completely sealed...Im assuming there is a air exchanger but ill confirm that, even if they did maybe it wasnt balanced correctly etc.. there used to be a paper mill in operation here for prolly 20 years of the houses life but cant see that really affecting anything as i never seen this type of blackened in any other place around here. it is weird like you said, why are only a few like that..


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## CAUSA (Apr 3, 2013)

Sparkied said:


> This is exactly what i was thinking, the home is air tight we live in northwestern ontario. Maybe there are drafts everytime a door is open to equalize the pressure in the home it comes straight through the top plate holes or maybe the vapor barrier around some of the outside boxes arent completely sealed...Im assuming there is a air exchanger but ill confirm that, even if they did maybe it wasnt balanced correctly etc.. there used to be a paper mill in operation here for prolly 20 years of the houses life but cant see that really affecting anything as i never seen this type of blackened in any other place around here. it is weird like you said, why are only a few like that..


House was built in 1989, and you state that it is now air tight.

that is a problem. The building should breathe. The combustion air is drawn from the building. With no proper air exchange this affects the combustion of the furnace and poor combustion leads to aldehydes in the flue gas which is corrosive.
So the building goes into an slight negative air during combustion. The unsealed area will draw in this mixture of out side air and particles of combustion.

In worst case, this affects the flue condition and leakage and the inhabitants.
Over time this will affect certain metals and certain components of the house.

look for the areas with the most corrosion discoloured areas and that is the leakage path area.

check the furnace and flue condition. And correction of the air exchange. This is a problem that can go south.

H2S smells like rotten eggs in a 2-5ppm environment.
Aldehyde smell slightly chemical/coal like. In a 3-8ppm environment. Where there is aldehydes there is CO this can kill.
If the heat is electric check the water tank. If all electric. there is sewer gas migration and the inside wall is a vent stack wall.


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## ohm it hertz (Dec 2, 2020)

Guys 

They sprayed the wall black during a remodel. It's black paint.

Edit: whoops, nevermind. I saw the walls are painted black, but all the wires would have black overspray on them. Strange.


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## joe-nwt (Mar 28, 2019)

CAUSA said:


> there is sewer gas migration and the inside wall is a vent stack wall.


Best answer so far. Might also be from a sump pit.


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## Bluenose for rent (Nov 6, 2020)

I’ve seen this before, every house of a certain age in an isolated flyin community up north. I never figured out what caused it, but it was on all the branch circuit bonding. I thought copper oxidization/corrosion was green, not black?


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## Majewski (Jan 8, 2016)

Lol jesus ppl. Its the Chinese walls.


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## splatz (May 23, 2015)

Are those boxes the same as in the rest of the house, original or cut in boxes?


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## wiz1997 (Mar 30, 2021)

Having worked in a sodium hypochorite plant for nearly ten years and seeing what it does to metals, I suspect the wires to have been exposed to the chemical.

Sodium Hypochorite is the chemical name for a common household cleaning product, bleach.

Bleach could have been used to kill off mold or cover up a DNA leak.

After Hurricane Harvey flooded my house and the sheetrock removed, the studs got a good spray of bleach up to about 4 feet.
But bleach loves eating up organic materials and must be neutralized to prevent the bleach from destroying anything organic such as wood.
Hydrogen peroxide can be used to neutralize bleach.

Hydrogen peroxide is also a common household cleaning product.
Advertised as color safe bleach or non-chlorine bleach.


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## taglicious (Feb 8, 2020)

^^Ding ding on wiz1997 post^^
I did remediation as well, and that is the exact reason for the discoloration. I lol because i started working/doing electrical years ago in homes that are being flipped and seen it while replacing receps. WEAR A DOUBLE FILTERED MASK in these ‘FLIPS’ because of the extenuating living conditions, or the house has been sitting for a length of time, you are subject to ‘airborne spores’. The year of the home is irrelevant to what you could be inhaling.


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## mburtis (Sep 1, 2018)

Yes sodium hypo will eat just about anything. We make it on site and even the super low strength stuff we use pretty much requires plastic as it eats most other things other than titanium. H2s is just as bad, every wire at the wastewater plant is discolored black like that. I've never noticed the corrosion on our hypo equipment but it's pretty well vented. I'll still take hypo over chlorine gas any day.


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## taglicious (Feb 8, 2020)

Mburtis, i used to work in a USDA inspected meat processing facility, and used the chlorine combo with a 200 degree boiler/pressure washer. Face masks during solution spray down, shields while rinsing. Awesome smell. 🤭 hazmat suits only lasted a couple weeks. Maintenance was a millwright who showed what happened to anything exposed. That was a life learning experience.


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## paulengr (Oct 8, 2017)

frankendodge said:


> Never worked around H2S before.. very interesting that it can do this. I want to know more.
> I would wonder why it is only affecting certain devices though.


Copper oxides can be greenish, bluish, red, or black. That’s just old wiring. Copper sulfides are black too but the crystals have more of a powdery look and other metals including those zinc coated terminals will turn black.


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## frankendodge (Oct 25, 2019)

While waiting for the wife to finish christmas shopping I went down the chineseium drywall/h2s rabbit hole. Interesting reading.
The sewer gas leak idea would be one to consider. I have seen so many poor plumbing installs/renos where a trap was not installed and sewer gas leaks out the drain. If the outlets in question are close to a bathroom, or over a utility room with a dried out floor drain that could be a source too. 
Is it a bedroom above a garage? Someone had batteries on a trickle charger or idled the car a lot maybe.
Moisture usually turns copper green. Black seems like chemical/acid corrosion.


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## WannabeTesla (Feb 24, 2020)

I've seen this once. Very interesting.


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## mccla5214 (Mar 7, 2021)

Sparkied said:


> This is exactly what i was thinking, the home is air tight we live in northwestern ontario. Maybe there are drafts everytime a door is open to equalize the pressure in the home it comes straight through the top plate holes or maybe the vapor barrier around some of the outside boxes arent completely sealed...Im assuming there is a air exchanger but ill confirm that, even if they did maybe it wasnt balanced correctly etc.. there used to be a paper mill in operation here for prolly 20 years of the houses life but cant see that really affecting anything as i never seen this type of blackened in any other place around here. it is weird like you said, why are only a few like that..


There you go, I've worked in many plants with H2S and paper pulp plants are one. The fact it's not worse is due to the plant shutting down, I've seen this so bad it flaked off busbars and was laying in the bottom of the cabinet. Every copper wire was black with it.


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## Slay301 (Apr 23, 2018)

The house was probably a Chinese meth lab


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## Slay301 (Apr 23, 2018)

Could be dissimilar metals from the device itself


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## Almost Retired (Sep 14, 2021)

Slay301 said:


> Could be dissimilar metals from the device itself


so this is the first time ever that a copper wire on a brass connection of the plug has ever turned black ?


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## Slay301 (Apr 23, 2018)

Almost Retired said:


> so this is the first time ever that a copper wire on a brass connection of the plug has ever turned black ?


Who said it’s brass ? Or who said the metal they used was pure could have been a bad mix. Who knows


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## Almost Retired (Sep 14, 2021)

Slay301 said:


> Who said it’s brass ? Or who said the metal they used was pure could have been a bad mix. Who knows


well if we are going to use substandard materials for this, then i cant argue with you. i have no experience with that


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## Slay301 (Apr 23, 2018)

Almost Retired said:


> well if we are going to use substandard materials for this, then i cant argue with you. i have no experience with that


**** who knows could have used aluminum rated devices I don’t know I could be and am probably wrong just like everyone else. All electricity runs on FM any ways… fudging magic


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## Majewski (Jan 8, 2016)

Slay301 said:


> Who said it’s brass ? Or who said the metal they used was pure could have been a bad mix. Who knows


I KNOW!


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## GrayHair (Jan 14, 2013)

Do you have sprayed insulation? Don't know what is used in sprayed insulation but could it be from off-gasing? Just a WAG.


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## paulengr (Oct 8, 2017)

mccla5214 said:


> There you go, I've worked in many plants with H2S and paper pulp plants are one. The fact it's not worse is due to the plant shutting down, I've seen this so bad it flaked off busbars and was laying in the bottom of the cabinet. Every copper wire was black with it.


Use electrical joint compound when replacing wires. Then paint terminations nails with liquid electrical tape. On stuff you can’t do that like RJ45 get a tub of silicone vacuum grease. Smear grease on connector then plug in. Always special order distribution panels with copper or aluminum bus bars only, NO silver coating!!

All of these things help create an air tight seal. Ideally you want to go silver free but because of RoHS all the circuit boards are loaded with silver solder. Conformal coating (DIY or orders) makes a major difference too.


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