ATOT electricians, weird ground problem

[natto fire]

Last weekend, I did a rush install/diagnostic at a friend's house, that turned into a headache (as all skilled favors do).

I found out that if the new circuit I installed was live, it made the grounding system hot as well. This included the water spigot, and some aluminum flashing at the bottom of the wood shaker siding.

Basically, when this breaker was on I got 15V from neutral to weak earth ground (probe in dense clay), but 110v from ground pin to weak earth ground!

As I was limited on time, I only checked the ground pin at one receptacle and multiple frame ground points, but considering the water spigot and flashing were live (this is how the homeowner discovered the fault, unfortunately) I am inclined to believe the grounding is either mis-wired, or there is some kind of strange fault which is not tripping a breaker.
I am going to go back this weekend and check a few things, as my temp solution has been to keep the circuit off.

Was hoping to get a few ideas as what to try to diagnose, going back this weekend. To clarify, the service in the house is fed from a 200A panel in the barn. It is 100A, fed underground by 2" PVC, they are Murray (Siemens) panels. Both panels have their own grounding rod, although the grounding rod at the house feels loose at the very top of the ground, not sure of the depth.

I know I am going to check the bare copper #6 wire that is going from the ground bus (neutral bond) through the foundation to the ground bar.

Most of the time, if I have a fault that results in the ground being "energized" there is either arc flash, tripped breakers, burned tools, or a combination of the three.

I have to inspect one NM connector going into a handy box. The shell of this box is live when the circuit is on, even if I isolate the hot at that junction from panel, so I know for sure the load side is good (switch leg, fixture, neutral and all, dedicated circuit)

TL;DR:

One circuit make ground OUCH! Not test all circuit I go back remote locale. What to do if earth shock you?

 

[arkcom]

They probably thought the black wire was supposed to be ground when they wired the house or something.

If it the ground wire was actually grounded I would think the breaker would trip.

 

[Red Squirrel]

Are all ground rods/points properly bonded?

Just for fun I would put a clamp meter around the water pipe and other pipes just to see if you get current and where. You'll want to put a small load on the circuit though.

Though, this sounds rather dangerous so I think I would just open up every single box of that circuit and look for where the fault is.

What I find odd is that the hot to ground did not cause a dead short as it should be bonded to neutral at the first panel. My uneducated guess is the fault is not directly to grounding conductor but actually to the ground as in a wire touching moist wall or floor or something.

 

[natto fire]

They probably thought the black wire was supposed to be ground when they wired the house or something.

If it the ground wire was actually grounded I would think the breaker would trip.

That is similar to what I assumed, but my circuit was clean as far as I know. I have been a commercial electrician for 2 years, with 3 years of "DIY" residential work.

I did get a weird arc when I powered on my circuit in a metal (handy box) receptacle that was part of the old structure (two piece home with part of the structure lacking a crawlspace or any significant foundation))
This was alleviated by turning that circuit on before the new one.

I still have to check two NM connectors, but even if one is shorted to ground, why wouldn't it burn out the wire like a proper ground fault, instead of lighting up the grounding system?

Are all ground rods/points properly bonded?

Just for fun I would put a clamp meter around the water pipe and other pipes just to see if you get current and where. You'll want to put a small load on the circuit though.

Though, this sounds rather dangerous so I think I would just open up every single box of that circuit and look for where the fault is.

What I find odd is that the hot to ground did not cause a dead short as it should be bonded to neutral at the first panel. My uneducated guess is the fault is not directly to grounding conductor but actually to the ground as in a wire touching moist wall or floor or something.

I am curious of the amperage as well, but regardless, there should not be enough to deliver a painful shock to someone who is grounded. I prefer to garden and walk about in beautiful fescue lawns barefoot, which is how this lady got shocked, and don't want her to fear doing this in the future!



Resistance to ground bar from the main service to ground rod was perfect. Did not have a chance to ensure the same at the house sub-panel, but noticed lots of play in the top of the ground rod.

 

[Kneedragger]

A long time ago I did some side work at a house and when I was working on a box I felt this pricking sensation against my arm. I couldn't see anything but it also felt like I was getting shocked. Turns out I was getting a low voltage 30v I think between one ground and my new one.

I might not be able to explain this all that well but when you have two different grounding system and they are never bonded together you can have a potential of voltage between the two. So you might want to make sure all grounding is tied together.

Also the grounding for the house might not have ever been adequate....

 

[pcgeek11]

As stated above he could have multiple ground points that are Not Common as they should be. All that would be needed then is to tie them together.

 

[pcgeek11]

AS I understand it the problem did not exist until you installed a new circuit.

I did a rush install/diagnostic at a friend's house

You need to redo or Undo your rushed circuit. Disconnect it and see if the problem goes away. Basic troubleshooting.

Working correctly.
Modified something.
Not working correctly.
= Something was done wrong.

 

[natto fire]

AS I understand it the problem did not exist until you installed a new circuit.



You need to redo or Undo your rushed circuit. Disconnect it and see if the problem goes away. Basic troubleshooting.

Working correctly.
Modified something.
Not working correctly.
= Something was done wrong.

You are correct, and as a stop gap I have turned off and "locked out" (with e-tape, not that this panel is accessible) the afflicted circuit.

Like I said, I have two NM connectors to troubleshoot to make sure they are not pinched, but from that handy-box to panel it is a clean run.

I will double check those connectors, but IMO, there might be a bigger problem if that box I installed does not have a true ground.

To reiterate, it is definitely a problem on my end, but it is strange to have a live "ground" so I was hoping to get some insight in the thread.

I still have some more diagnosis before I pinpoint the problem, but it is safe to say something might be wrong with my home run to panel, and I might have a new symptom for the book, regarding ground fault.

 

[pcgeek11]

Reading back in your first post I think you pin pointed the actual problem:

Was hoping to get a few ideas as what to try to diagnose, going back this weekend. To clarify, the service in the house is fed from a 200A panel in the barn. It is 100A, fed underground by 2" PVC, they are Murray (Siemens) panels. Both panels have their own grounding rod, although the grounding rod at the house feels loose at the very top of the ground, not sure of the depth.

As you stated they have their own grounding rod. That being said they should also be tied together with a common grounding point wire through the PCV Conduit. If not that is a very real possibility of what is causing your problem.

Please update us when you get the problem solved.

I did not mean to sound snarky above if you took it that way.

 

[skull]

Reading back in your first post I think you pin pointed the actual problem:



As you stated they have their own grounding rod. That being said they should also be tied together with a common grounding point wire through the PCV Conduit. If not that is a very real possibility of what is causing your problem.

Please update us when you get the problem solved.

I did not mean to sound snarky above if you took it that way.

This was common til 05 I think. OP find you're short and bond the sub to neutral. Better yet pull a 4th wire if you can.

 

[natto fire]

Reading back in your first post I think you pin pointed the actual problem:



As you stated they have their own grounding rod. That being said they should also be tied together with a common grounding point wire through the PCV Conduit. If not that is a very real possibility of what is causing your problem.

Please update us when you get the problem solved.

I did not mean to sound snarky above if you took it that way.

Yeah, I was wondering about that, as I remember having to bond the ground bars together of sub-panels, but the fact that the potential goes to zero when I turn off the new circuit made me not explore that possibility more.

I will update when I make it back there (going to try to go this weekend).

I took no offense to anything you have said, and appreciate the help. :thumbsup:

 

[imagoon]

Besides the above listed, also check your grounding in the new circuit. Make sure you didn't scuff a neutral. Shutdown power to the circuit, disconnect all loads and do wire isolation testing. Missing a ground and a scuffed neutral can energize the floating (and isolated) ground paths.

 

[Greenman]

Sounds like the new circuit is shorted and the neutral is at least partially burned off.

 

[amdhunter]

Have you tried this troubleshooting step?

 

[Greenman]

Have you tried this troubleshooting step?

That moron has the hot and ground reversed.

 

[pcgeek11]

Any Updated info? Curiosity is killing me. :\

 

[TurtleCrusher]

...and you're an electrician? I presume not a well trained union electrician, because first thing first you need to make sure grounding and bonding is done properly. As others have mentioned, there can be a huge difference of potential between grounded circuits. This is electrical ABC's.

This is the reason soldiers in Iraq and Afghanistan were getting bit and killed by showering. Contractors were hiring shit ass know-nothing electricians who couldn't even comprehend a working, safe grounding system.

I'm not trying to be an asshole, but if you don't know grounding and bonding you need to revisit your apprentice materials. Doing skilled work without the skill is gross negligence on your part. Don't do side-work unless you truly know your shit. As an apprentice I have no idea if I'll ever be that confident on anything besides my own home.

 

[balloonshark]

I've seen a single strand of stranded wire on an electrical outlet cause a bonded neutral before.

On that same job our supervisor took a shortcut and used a ground wire as a positive wire instead of tearing into a wall. I would hate to be the maintenance guy at that hotel.

I've also seen a trouble light with a metal shroud short out and put voltage on the steel gas pipe it was hanging on. I kept telling them the light was shocking me but they didn't believe me. They found out later when the guy wearing glasses touched his glasses against the pipe upstairs lol.

 

[TurtleCrusher]

I've seen a single strand of stranded wire on an electrical outlet cause a bonded neutral before.

On that same job our supervisor took a shortcut and used a ground wire as a positive wire instead of tearing into a wall. I would hate to be the maintenance guy at that hotel.

I've also seen a trouble light with a metal shroud short out and put voltage on the steel gas pipe it was hanging on. I kept telling them the light was shocking me but they didn't believe me. They found out later when the guy wearing glasses touched his glasses against the pipe upstairs lol.

Dear Lord

 

[pcgeek11]

...and you're an electrician? I presume not a well trained union electrician, because first thing first you need to make sure grounding and bonding is done properly. As others have mentioned, there can be a huge difference of potential between grounded circuits. This is electrical ABC's.

This is the reason soldiers in Iraq and Afghanistan were getting bit and killed by showering. Contractors were hiring shit ass know-nothing electricians who couldn't even comprehend a working, safe grounding system.

I'm not trying to be an asshole, but if you don't know grounding and bonding you need to revisit your apprentice materials. Doing skilled work without the skill is gross negligence on your part. Don't do side-work unless you truly know your shit. As an apprentice I have no idea if I'll ever be that confident on anything besides my own home.

Being in a union has NOTHING to do with being a good electrician or not. I for one have been an electrician for 35 years. I have known Union Electricians that were idiots and Non-Union Electricians that were also idiots. I have never been in a Union and I never will be. Thank god, I don't have the need or desire to pay someone for the right to work.

I do however think you are trying to be an asshole. Everyone makes mistakes, Everyone. Even you. The only person that don't make mistakes is the one that does nothing. Maybe your are that one. You are only an Apprentice and talking shit? Hmmm.

 

[natto fire]

Any Updated info? Curiosity is killing me. :\

Didn't make it back there this weekend. Circuit is still off, no one is getting shocked. I will update as soon as I go back, but I am thinking more and more that the connector has pinched through the insulation.

...and you're an electrician? I presume not a well trained union electrician, because first thing first you need to make sure grounding and bonding is done properly. As others have mentioned, there can be a huge difference of potential between grounded circuits. This is electrical ABC's.

This is the reason soldiers in Iraq and Afghanistan were getting bit and killed by showering. Contractors were hiring shit ass know-nothing electricians who couldn't even comprehend a working, safe grounding system.

I'm not trying to be an asshole, but if you don't know grounding and bonding you need to revisit your apprentice materials. Doing skilled work without the skill is gross negligence on your part. Don't do side-work unless you truly know your shit. As an apprentice I have no idea if I'll ever be that confident on anything besides my own home.

For the record, I did not install the service, and since it had been working fine as is, did not think about the missing common ground wire. I get where you are coming from, since most home fires start from bad electrical work. I know I shouldn't have rushed while doing this work, and try to take electrical safety very seriously. I am not a union electrician, and actually only have 3 years professional experience.

It was supposed to be a simple branch circuit installation, that turned into service repair. The service was installed by the homeowners late husband and has functioned fine for over 14 years. I will run a common grounding wire between the two panels, although neither one has separate grounding bars with all grounds landed with the neutrals.

I can assure you I have never been to Iraq, and in fact, know something, which is the only irrelevant part of your post. The lady I am doing this for cannot afford an electrician, and I have installed hundreds, if not thousands of branch circuits before, with minimal problems. Again, I get where you are coming from chastising my work, as electrical safety is a big deal, it is fire in a wire, after all.

 

[pcgeek11]

Updates????????????????????

 

[jad1097]

That is similar to what I assumed, but my circuit was clean as far as I know. I have been a commercial electrician for 2 years, with 3 years of "DIY" residential work.

.

Didn't read anything after the quote above.

Tell the person to hire an experienced electrician immediately! You need to stop doing electrical work by yourself because you do not have enough experience or knowledge to do so!

People like you kill people! No, I am not fucking joking! I'm a journeyman wireman who has been in the trade since 1985 You're welcome