Blackened ground wires, Why??

[Erby]

I seem to remember something about grounds being disconnected and chemicals as causes for blackened ground wire in the panels.

Anyone want to refresh my memory with details worthy of report inclusion?

Details.

House is unoccupied. Crawl space is VERY wet. Electrical panel is in laundry room. Trap door for crawl space is also in laundry room with open dryer vent pipe hole thru floor. Most of the ground wires were BLACK. Sump pump wasn't operating until it was turned on at the breaker. Smelling the water at the sump pump discharge was kinda like that rotten egg odor we used to get in chemistry lab. Wasn't that sulphur? (Didn't smell it in the crawl space because of the mask).

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Your thoughts?

[Scottpat]

My first thought is Yuk!

Erby, when I have found blackened copper it has always been in a room or garage that has had chemicals stored in close proximity to the panel.

You said the water had a "sulphur" smell. Does the area have sulphur water? If ground water is seeping up into the crawl space and it is sulphur water, I would bet that could be the culprit that is turning the copper black in the panel.

[Brandon Chew]

The rotten egg odor is due to sulfide gas (typically hydrogen sulfide) dissolved in and being released from the water. It could be present in the groundwater naturally ("sulfur water") or it can be formed when organic matter rots in an oxygen depleted environment. Sulfide gas has a very low odor threshold and you can smell it at very low concentrations. At even lower concentrations it will corrode copper, turning it black.

I suspect your blackened ground wires are caused by sulfide gas migrating up from the crawl and into the house. You should find the corrosion on any exposed copper in that area, not just the ground wires (terminal screws, stripped ends of hot conductors, electrical contacts, splices, etc.).

As Scott mentioned, another possible cause could be laundry chemicals.

They obviously need to dry out the crawl and fix any damage caused by high moisture down there. Then there's the issue of what kind of damage is done to the electrical system and your recommendations on what they should do about it.

[hausdok]

Hi,

Yeah, my first guess would have been hydrogen sulfide too. However, laundry rooms have stuff like bleach in them and corrosive chemicals in laundry detergent. Mix them into the hot water of a washing machine and small amounts of those chemicals waft into the air and might react with those cold equipment grounding conductors.

ONE TEAM - ONE FIGHT!!!

Mike

[Richard Stanley]

National Electric code. 110.12© Integrity of Electrical Equipment and Connections. Internal parts of electrical equipment, including busbars, wiring terminals, insulators, and other surfaces, shall not be damaged or contaminated by foreign materials such as paint, plaster, cleaners, abrasives, or corrosive residues. There shall be no damaged parts that may adversely affect safe operation or mechanical strength of the equipment such as parts that are broken; bent; cut; or deteriorated by corrosion, chemical action, or overheating.

[Brandon Chew]

Originally posted by hausdok

Hi,

Yeah, my first guess would have been hydrogen sulfide too. However, laundry rooms have stuff like bleach in them and corrosive chemicals in laundry detergent. Mix them into the hot water of a washing machine and small amounts of those chemicals waft into the air and might react with those cold equipment grounding conductors.

ONE TEAM - ONE FIGHT!!!

Mike

Yeah, but the thing about that is that the black color is a tell-tale of sulfide corrosion. With laundry chemicals you usually get chloride (from bleach), ammonia, or sulfate corrosion on copper, which give you your pretty shades of blue-greens and whites.

[Jim Katen]

Originally posted by Erby

I seem to remember something about grounds being disconnected and chemicals as causes for blackened ground wire in the panels.

Anyone want to refresh my memory with details worthy of report inclusion?

Details.

House is unoccupied. Crawl space is VERY wet. Electrical panel is in laundry room. Trap door for crawl space is also in laundry room with open dryer vent pipe hole thru floor. Most of the ground wires were BLACK. Sump pump wasn't operating until it was turned on at the breaker. Smelling the water at the sump pump discharge was kinda like that rotten egg odor we used to get in chemistry lab. Wasn't that sulphur? (Didn't smell it in the crawl space because of the mask).

Your thoughts?

Sulfur compounds will cause copper to turn black. This is a fact and is not disputable. Anyone can confirm this by exposing some copper to hydrogen sulfide gas.

The idea that copper turns black because of problems with grounding or because of stray currents is false. This myth needs to die.

In your case, the blackening is certainly caused by the noxious contaminants in the air.

- Jim Katen, Oregon

[msteger]

Due to what you are seeing, I would address any moisture issues in the crawl space. I would also recommend having a licensed electrician evaluate the exposed ground wires to determine if they have been compromised by the sulfur issue.

[Scottpat]

The black oxidation is not going to hurt anyting with the panel.

Recommending an electrician is a CYA step that some folks take. It is up to you to decide on the next step.

[Erby]

Jim. But, is it going to harm the wire any??

[Jim Katen]

Originally posted by Erby

Jim. But, is it going to harm the wire any??

It might, if there is enough corrosion. I did some experiments with copper in an atmosphere of hydrogen sulfide and was able to get the surfaces of the copper to actually flake away -- as rust flakes away from iron. Admittedly, I was producing an extreme reaction under controlled conditions that you're unlikely to get in an actual house.

I'd look at the actual connections. If they looked & felt sound, I wouldn't worry about the existing blackening. Of course, I'd recommend that the future owners fix the conditions that lead to it.

If you're interested, here's a sequence of pictures of my experiment.

- Jim Katen

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[Erby]

For some strange reason, I've found that I'm almost always interested in what ALL the members of this board have to say about stuff.

Thanks for the information.

[Les]

Jim, what was the time line? Were you "overcharging" the battery?

[Scottpat]

I like Jim's watch band!

[Jim Katen]

Originally posted by Les

Jim, what was the time line? Were you "overcharging" the battery?

The elapsed time from the first picture to the last was just short of 5 days. (4 days, 23 hours and 24 minutes)

I was certainly overcharging the battery to create the corrosive atmosphere inside the bag. Without overcharging, the battery wouldn't have given off much gas.

- Jim Katen, Oregon

[Les]

I kinda knew that, but you could have put a little "XR7" or epsom salt into it.

I'm sure you know that hydrogen sulfide is leathal in very low ppm. Keep the cat and kids at a safe distance.

[Jim Katen]

Originally posted by Les

I kinda knew that, but you could have put a little "XR7" or epsom salt into it.

You lost me. What's XR-7? (Besides a Mercury Cougar or a Ricoh camera?) What would I put the epsom salt into?

I'm sure you know that hydrogen sulfide is leathal in very low ppm. Keep the cat and kids at a safe distance.

Well, the kids anyway. The cats are on their own.

I should probably have explained that this was outdoors, under an overhang adjacent to my old woodshed.

Just in case anyone wants to repeat the experiment, not only is hydrogen sulfide lethal, but the battery will also produce oxygen. The combination of gases is explosive so you want to do this out in the open air well away from any sources of ignition (besides the clamp connections to the battery terminals, which can spark). Unless, of course, an explosion is your goal.

- Jim Katen, Oregon

[Brandon Chew]

Sulfur compounds will cause copper to turn black. This is a fact and is not disputable.

A small correction is needed to fine-tune that statement. Sulfides will turn copper black. Sulfates will turn it blue-green. Both are sulfur compounds.

I'm sure you know that hydrogen sulfide is leathal in very low ppm.

The odor threshold is extremely low, 0.0047 ppm.

Eye irritation begins at about 10 ppm.

Most people can tolerate 50-100 ppm for several hours, but after about an hour the eye irritation becomes more pronounced and you'll start to get respiratory tract irritation and minor coughing.

At concentrations below about 100 ppm, the smell and the eye irritation should alert you to move away to safety. The problem is that you usually walk into an area and the concentration is whatever it is, and doesn't build gradually over time. If it's over about 200 ppm -- it paralyzes the olfactory nerve after a couple of sniffs, and with your loss of smell you lose your awareness of the danger. The lethal concentration at which 50% of humans would die (LC50) after 5 minutes of exposure is 800 ppm. At concentrations over 1000 ppm, one sniff can cause collapse, loss of breathing, and death.

Fortunately for us as home inspectors, it is rare for us to encounter lethal levels of hydrogen sulfide. If you can smell the rotten eggs you are probably ok as long as you can smell it -- but if you smell it and then the smell goes away, don't assume the gas has gone away.

The greater danger to HIs comes from the environment that produces it, and the fact that it is heavier than air. It is produced in a low oxygen environment. Being heavier than air, it displaces the oxygen and pools in low places like basements, crawlspaces, manholes, sumps, empty used septic tanks, and pump station wet wells. You are more likely to die from lack of oxygen than from the hydrogen sulfide itself. The same conditions that generate the hydrogen sulfide also tend to generate methane (natural gas). Hydrogen sulfide and methane are both highly flammable, and if the concentration of either one is within their respective lower and upper explosive limits, you have the added threat of explosion and fire.

Erby - re: what to do with your panel. This is a case where I think handing the ball off to a qualified electrician for a thorough inspection makes a lot of sense. Let him make the call if the corrosion warrants repair or replacement.

[Les]

Jim, XR7 was an old product for renewing an auto battery. Epsom salt will cause the plates to sulfate and/or give the battery a little more temporary life. 1/2 tsp per cell. Just one of the old tales that I can vouch for.

Brandon, looks like you did a little research on hydrogen sufide. I believe you should fine tune those figures. I personally know two men that were killed by exposure; both instantly! I was a partner in an oilfield service company that serviced "sour" wells here in Michigan.

I presently have a son and family that live in an area that has operational "sour" wells.

Scott Air-pac breathing devices are always carried when working around those wells.

Don't fool around with the gas - it will kill you!

[Brandon Chew]

Brandon, looks like you did a little research on hydrogen sulfide. I believe you should fine tune those figures.

I looked up the actual toxicity numbers from a couple of different sources before I posted them. There is some variability depending on the source, but the numbers I posted are in the ballpark, and are meant to show the relative differences from one concentration to the next.

Except for grabbing the numbers, the rest of the post comes from stuff I learned over a span of about 20 years where I inspected, designed, operated, and taught others how to operate industrial and municipal wastewater treatment plants and collection systems, had to determine safe levels of toxic and non-toxic substances for limits in their discharge permits, and brought enforcement actions against those who violated their permits, all for the purpose of helping to protect the water quality for a state of about 19 million people. Workers in wastewater treatment plants and collection systems, like those in the oil services industry, face very real on-the-job threats from hydrogen sulfide gas.

I personally know two men that were killed by exposure; both instantly! I was a partner in an oilfield service company that serviced "sour" wells here in Michigan.

That must have been a sad and heart-wrenching experience to go through... my condolences to you and to their families. I knew two men that were killed when one of them dropped the "trouble light" that they were using to peer into the open roof hatch of an anaerobic digester. They had emptied the digester the previous day and were preparing to clean it out. Methane and hydrogen sulfide gas formed and was released from the residual waste in the bottom of the tank. It accumulated overnight creating an explosive atmosphere inside the tank. When the guy dropped the trouble light, the bulb broke, and a tank the size of a large house exploded while the two men were standing on top of it.

Les, if you don't mind me asking, what was the concentration of hydrogen sulfide in that incident that instantly killed the two men? Lethality depends upon route of entry (in this case inhalation), duration (in this case instantly), and concentration. I posted "at concentrations over 1000 ppm, one sniff can cause collapse, loss of breathing, and death." I would guess that it was over 1000 ppm. Levels that high would be unusual for a sewage plant worker to encounter, or for a home inspector or a homeowner, unless he was doing a science experiment on his kitchen table. [] Workers at some industrial wastewater treatment plants face a higher risk, depending upon the chemicals and production practices involved at that particular site.

Scott Air-pac breathing devices are always carried when working around those wells.

I don't know much about the oil drilling or services industry. It sounds like the risks of encountering lethal concentrations of hydrogen sulfide are very real. Do they do much work in enclosed areas and confined spaces? Do they have to worry about it when working out in the open air too? I'd guess that they do.

I presently have a son and family that live in an area that has operational "sour" wells.

Do the folks who live in these areas need to worry about hydrogen sulfide gas seeping into their basement or crawlspace from the ground? If so, I think they would deal with it the same way that you would deal with high radon levels. Do they need to worry about being downwind from a well that could release hydrogen sulfide gas into the air?

Don't fool around with the gas - it will kill you!

I'd change "will" to "can", but I have no argument with that. If you have a concentrated source of hydrogen sulfide gas, you definitely don't want to stick your nose on it. One whiff can kill you.

The point I am making is that for home inspectors and homeowners who encounter hydrogen sulfide in the home, the risk of dying from breathing the gas is a lot less than the risk of dying from lack of oxygen or the risk of being injured by an explosion. (I recall a thread here on TIJ a while back regarding exploding dishwashers in houses that have been vacant for a while).

I'm just trying to provide some information to fill the space between Erby crawling around in a crawlspace with some hydrogen sulfide in it, and Les saying it is lethal in very low ppm.

[Les]

Brandon,

Oilfield workers often are at the wellhead or related components of sour gas wells. Both men were killed instantly while changing a pressure gauge on the wellhead. Likely a couple cubic foot of gas actually escaped. The outside temp was below zero and changing gauges was something they did everyday. Neither one moved an inch before they died.

In Michigan most sour gas is at or beyond 5,000 ft and is not a surface gas issue. I know of no sour gas accidents involving civilians in Michigan.

Thank you for your post and comments - it just may save a life!

[mridgeelk]

Hydrogen sulfide is called "stinkdamp" in the mining industry, much more of a problem in hard rock mines than coal mines. It is one of the reasons parakeets used to be carried by

miners.

Originally posted by Brandon Chew

Sulfur compounds will cause copper to turn black. This is a fact and is not disputable.

A small correction is needed to fine-tune that statement. Sulfides will turn copper black. Sulfates will turn it blue-green. Both are sulfur compounds.

I'm sure you know that hydrogen sulfide is leathal in very low ppm.

The odor threshold is extremely low, 0.0047 ppm.

Eye irritation begins at about 10 ppm.

Most people can tolerate 50-100 ppm for several hours, but after about an hour the eye irritation becomes more pronounced and you'll start to get respiratory tract irritation and minor coughing.

At concentrations below about 100 ppm, the smell and the eye irritation should alert you to move away to safety. The problem is that you usually walk into an area and the concentration is whatever it is, and doesn't build gradually over time. If it's over about 200 ppm -- it paralyzes the olfactory nerve after a couple of sniffs, and with your loss of smell you lose your awareness of the danger. The lethal concentration at which 50% of humans would die (LC50) after 5 minutes of exposure is 800 ppm. At concentrations over 1000 ppm, one sniff can cause collapse, loss of breathing, and death.

Fortunately for us as home inspectors, it is rare for us to encounter lethal levels of hydrogen sulfide. If you can smell the rotten eggs you are probably ok as long as you can smell it -- but if you smell it and then the smell goes away, don't assume the gas has gone away.

The greater danger to HIs comes from the environment that produces it, and the fact that it is heavier than air. It is produced in a low oxygen environment. Being heavier than air, it displaces the oxygen and pools in low places like basements, crawlspaces, manholes, sumps, empty used septic tanks, and pump station wet wells. You are more likely to die from lack of oxygen than from the hydrogen sulfide itself. The same conditions that generate the hydrogen sulfide also tend to generate methane (natural gas). Hydrogen sulfide and methane are both highly flammable, and if the concentration of either one is within their respective lower and upper explosive limits, you have the added threat of explosion and fire.

Erby - re: what to do with your panel. This is a case where I think handing the ball off to a qualified electrician for a thorough inspection makes a lot of sense. Let him make the call if the corrosion warrants repair or replacement.

[Sodapop]

Originally posted by Erby

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Your thoughts?

Erby: I hope your tetnis shot is up to date.

[hausdok]

Originally posted by Sodapop

Originally posted by Erby

Erby: I hope your tetnis shot is up to date.

Not braggin' but a crawl like that is just another day around here in crawlspace land.

OT - OF!!!

M.

[Jeremy]

Forgot what I was searching for now, but this old post caught my attention.

Years ago I had a new water well put in that produced way more water than we could measure, but also produced gas with the really strong rotten egg smell. Not having anymore money to throw in the ground at the time, I connected to that well for about 5, 6 months til I could drill again in another location. During that short period of time all the copper in the place turned black, the plumbing fixtures corroded, silver corroded, cheap jewelery became junk, I lost a few electronic items, and the colorfully painted beer stein from Germany turned grey/silver. Interestingly the red came back, but none of the other colors. Bad stuff man.

I can't tell from the picture, but it looks like this house could be in the country and likely served by a water well.

Erby, would that be an accurate guess?

I don't know if my situation had any affect on the building wire besides appearance; I would say probably not. Does anyone know if the hardness (or softness) of the copper could be changed by exposure to this gas? I did have a jeweler tell me one time that clorox bleach could change the properties of gold enough to make it more brittle. I suppose he could have been blowing smoke at me. I'm not a chemist. (May be a good thing!)

At any rate, if I were to encounter a property like this now, electrical concern aside, the issue would definately be worth bringing to the client. It was pretty nasty stuff to live with and costly. Might explain why the house was vacant.