# Conduit as EGC



## Salvatoreg02 (Feb 26, 2011)

Why do some many of us additional install an EGC in our conduits when the conduit can be used as the EGC. Do most of you prefer to use the conduit as the EGC or prefer to install an EGC instead regardless?


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## wildleg (Apr 12, 2009)

why do some of us beat dead horses over and over ?


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## 480sparky (Sep 20, 2007)

Gee. I dunno why.


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## wildleg (Apr 12, 2009)

so stop forgetting to tighten the fittings


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## 480sparky (Sep 20, 2007)

wildleg said:


> so stop forgetting to tighten the fittings



I'll be sure to dig those guys up and tell 'em.


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## Wirenuting (Sep 12, 2010)

Because some other electrician likes to move things that are in their way.


edit: it was that 1900 box with extension ring that I was trying to get into. They blocked it a little also.


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## itsunclebill (Jan 16, 2007)

At least one local AHJ has an amendment that requires it - for the reason in the pictures.


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## chicken steve (Mar 22, 2011)

the fault path would parrallel both a pulled in egc as well as mettallic pipe, even if said pipe were not considered an ecg....~CS~


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## 480sparky (Sep 20, 2007)

chicken steve said:


> the fault path would parrallel both a pulled in egc as well as mettallic pipe, even if said pipe were not considered an ecg....~CS~



And the issue would be..............? :001_huh:


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## Shockdoc (Mar 4, 2010)

I don't run an EGC unless it's medical with metallic conduit.


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## BBQ (Nov 16, 2010)

itsunclebill said:


> At least one local AHJ has an amendment that requires it - for the reason in the pictures.


Yeah that makes sense.

Do they also prohibit wirenuts as I find EGCs pulled out of those as well. :thumbsup:


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## Shockdoc (Mar 4, 2010)

EGCs have been helpful for pulling additional ckts in an existing conduit.


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## user4818 (Jan 15, 2009)

BBQ said:


> Yeah that makes sense.
> 
> Do they also prohibit wirenuts as I find EGCs pulled out of those as well. :thumbsup:



As I've said before, have you ever noticed in just about any junction box on a commercial job how anywhere from 8-15 #12's manage to fit in a red wirenut?


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## Big John (May 23, 2010)

Peter D said:


> As I've said before, have you ever noticed in just about any junction box on a commercial job how anywhere from 8-15 #12's manage to fit in a red wirenut?


 It's only wrong when they have to crank the red wirenut so hard it turns white. Kinda like a pop-up turkey timer, it lets you know when you're done. :whistling2:

-John


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## itsunclebill (Jan 16, 2007)

BBQ said:


> Yeah that makes sense.
> 
> Do they also prohibit wirenuts as I find EGCs pulled out of those as well. :thumbsup:


I only seem to find that on MWBC neutrals.


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## brian john (Mar 11, 2007)

Not that I condone sloppy work, but in all the pictures shown the structures were metallic and the ground was not comprised from a fault path perspective. NOT THAT I WANT TO COUNT ON THAT. 



Local amendment, personal choice or specifications.


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## Roger. (Dec 18, 2011)

In most installations conduit or tubing is a much better conductor than a wire regardless of the size of the wire. This is the reason for 517.13(A)

The "what if" a coupling pulls loose argument is weak. When an installation is sorry or there is "after the fact" damage it can very easily mean a wire conductor type EGC has been compromised.

The fact is that in the pictures posted the egc continuity is still in tact whereas with a broken wire it would not be.

Roger


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## Big John (May 23, 2010)

Roger. said:


> ...The fact is that in the pictures posted the egc continuity is still in tact whereas with a broken wire it would not be....


 This does not make sense. The EGC is intact in those pictures only because current will flow through the adjascent metallic objects, which is the same path it would also be forced to take if a wire broke.

-John


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## Roger. (Dec 18, 2011)

Big John said:


> This does not make sense. The EGC is intact in those pictures only because current will flow through the adjascent metallic objects, which is the same path it would also be forced to take if a wire broke.
> 
> -John


You're missing the point, in the pictures we are dealing with metal structural members and yes, if a wire type EGC is in parallel with the tubing the path is still in place through the metal conduit and the structural members which combined is the primary path, the wire by itself can not do this can it? 

I have not said using both is not a good idea but, if someone wants to put the dreaded "what if" in a disscussion, the probability of a wire being broke is as much a "what if" as the conduit coming apart is.

Roger


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## don_resqcapt19 (Jul 18, 2010)

480sparky said:


> Gee. I dunno why.


So why would expect that the installer that did this type of work would be any more careful with the terminations of an EGC of the wire type?


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## BBQ (Nov 16, 2010)

don_resqcapt19 said:


> So why would expect that the installer that did this type of work would be any more careful with the terminations of an EGC of the wire type?


Bingo, these pulled apart couplings are usually the result of sloppy work to start with, not tightening couplings, insufficient supports, wrong product for the application, poor choice of routes etc.


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## user4818 (Jan 15, 2009)

don_resqcapt19 said:


> So why would expect that the installer that did this type of work would be any more careful with the terminations of an EGC of the wire type?


It's a frequently employed strawman argument to use poor workmanship and/or carelessness to disallow something that is safe and code compliant. 

Carrying the "what if" scenarios to their logical conclusion, we should stop using electricity all together.


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## Big John (May 23, 2010)

Roger. said:


> You're missing the point, in the pictures we are dealing with metal structural members and yes, if a wire type EGC is in parallel with the tubing the path is still in place through the metal conduit and the structural members which combined is the primary path, the wire by itself can not do this can it...?


 I'm not sure I understand what you're saying, but if a conduit carrying a wire EGC was broken, I would expect the wire to continue to function as an EGC, and because it is bonded to all the equipment and boxes, it would also be using the building steel as a parallel path.

Long story short: In a metal building I think conduit EGC or wire EGC are equal. In a wooden building, I think a wire EGC is superior.

-John


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## wildleg (Apr 12, 2009)

so we should outlaw wooden buildings too ?


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## B4T (Feb 10, 2009)

I once had a guy work for me who would forget to tighten set screws.. drove me nuts.. 

Once was an accident.. twice and we have a problem.. I used to double check his work.. BIG waste of time.. :no:

It was down hill from there.. he lasted less than a year.. one of the reason why I like working alone..

Another guy had a problem following instructions.. when we finish a job EVERYTHING gets checked..

We did a dormer.. finished it up.. got home and a phone call from customer.. phone jack doesn't work.. :blink::blink:

I had one of the jack testers.. green light good.. red light.. reversed polarity..

Next day I asked him if he checked all (3) phone jacks.. YES..

I go back to the job and one of the wires fell off due to his great mechanical skills..

I always make up the room jacks first and then tie into the phone co. box..

So I asked how could the green or red light come on if a wire fell off.. :blink::blink:

He swore up and down he checked it.. 

Another guy who didn't last to the one year mark..


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## Big John (May 23, 2010)

wildleg said:


> so we should outlaw wooden buildings too ?


 Now you're catching on.

-John


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## 480sparky (Sep 20, 2007)

don_resqcapt19 said:


> So why would expect that the installer that did this type of work would be any more careful with the terminations of an EGC of the wire type?


If EMT should not be allowed to be an EGC because of occasional poor workmanship, perhaps THHN should not be allowed as well.


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## chicken steve (Mar 22, 2011)

well, we essentially have _both _with TH pulled in as an ecg 480.....~CS~


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## 480sparky (Sep 20, 2007)

chicken steve said:


> well, we essentially have _both _with TH pulled in as an ecg 480.....~CS~


But the detractors say if you're sloppy installing EMT, you're sloppy installing THHN, so neither one must be worth a damn.


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## user4818 (Jan 15, 2009)

480sparky said:


> If EMT should not be allowed to be an EGC because of occasional poor workmanship, perhaps THHN should not be allowed as well.





480sparky said:


> But the detractors say if you're sloppy installing EMT, you're sloppy installing THHN, so neither one must be worth a damn.


Stop being a tool. Nobody has said that.


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## chicken steve (Mar 22, 2011)

480sparky said:


> But the detractors say if you're sloppy installing EMT, you're sloppy installing THHN, so neither one must be worth a damn.


that the slobs get one outta two right was my point 480.....~CS~


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## Roger. (Dec 18, 2011)

480sparky said:


> But the detractors say if you're sloppy installing EMT, you're sloppy installing THHN, so neither one must be worth a damn.


Correct if installed by slobs, otherwise, if installed correctly by craftsmen the conduit or tubing is a great EGC and in many cases actually supperior to a wire. 


Roger


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## Shockdoc (Mar 4, 2010)

slobs....:laughing::laughing::laughing:


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## McClary’s Electrical (Feb 21, 2009)

Shockdoc said:


> EGCs have been helpful for pulling additional ckts in an existing conduit.


 
I did exactly that this week. I used the EGC's that were already in the conduit, to pull in over 1500 ft of extra circuits. I pulled the wire equipment grounds out and they will be scrapped.


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## 480sparky (Sep 20, 2007)

Roger. said:


> Correct if installed by slobs, otherwise, if installed correctly by craftsmen the conduit or tubing is a great EGC and in many cases actually supperior to a wire.
> 
> 
> Roger


According to Soares, it IS a far superior method.


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## brian john (Mar 11, 2007)

If you personal preference (not code mandated not in the specifications) is to install an EGC with every feeder and branch circuit I say go for it. What does get me is those that think because they install a copper EGC they are somehow have a superior installation or are better that others that choose not to install a copper EGC. When in reality they may not have a full understanding of all factors involved.


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## RIVETER (Sep 26, 2009)

Roger. said:


> Correct if installed by slobs, otherwise, if installed correctly by craftsmen the conduit or tubing is a great EGC and in many cases actually supperior to a wire.
> 
> 
> Roger


Absolutely, and it has been proven through testing that in a proper conduit system that also has a wire in it, when a fault current does occur about 95% of it will go through the conduit.


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## itsunclebill (Jan 16, 2007)

A bad installation is one thing. I'm sure everybody's been in a commercial area where somebody demo'd a wall that had a box or two in it and one or more fittings got loosened and pulled off the conduit so things could be repositioned and securely remounted with duct tape or bailing wire. These folks have no clue the conduit functions as a ground and won't do anything to get it fixed till a fire or insurance inspector busts their chops.


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## Big John (May 23, 2010)

brian john said:


> ...What does get me is those that think because they install a copper EGC they are somehow have a superior installation....


 Well, we'll agree to disagree on this. I base it solely on the fact that I've seen an awful lot of conduit get damaged and pull apart through no fault of the installing electrician. 

If having a conductor in there helps ensure the continuity of the EGC that might otherwise be lost, you'd have a hard time convincing me how that's not better.

-John


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## don_resqcapt19 (Jul 18, 2010)

480sparky said:


> But the detractors say if you're sloppy installing EMT, you're sloppy installing THHN, so neither one must be worth a damn.


Nothing wrong with the products...just with the installers.


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## BBQ (Nov 16, 2010)

Big John said:


> Long story short: In a metal building I think conduit EGC or wire EGC are equal. In a wooden building, I think a wire EGC is superior.
> 
> -John


So in a wooden building wired with either NM or PVC would you run two independent EGCs because all it takes is one bad EGC splice and you have no EGC?


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## Wireman191 (Aug 28, 2011)

Ever had to go fix a broken conduit and grab one end, then the other and get the living crap zapped out of you... not a good feeling.:no:


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## RePhase277 (Feb 5, 2008)

Wireman191 said:


> Ever had to go fix a broken conduit and grab one end, then the other and get the living crap zapped out of you... not a good feeling.:no:


I was working on my own A/C condensing unit yesterday. Because I was troubleshooting, the circuit was on. I took the cover off, knelt down on the ground, put my hand on the unit to prop myself up and BLAMO!

A 10-3 w/o ground comes in and the white is used to ground it, but at the panel it's a 10-2 w/ ground... so I found the boxless splice in the crawl space where some handy hack failed to tie the grounds together. So I fixed that, bad news is I need a new compressor.


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## swimmer (Mar 19, 2011)

480sparky said:


> Gee. I dunno why.


I see the same all the time with EMT and Flex. Rigid corrodes clean through. So always run EGC in conduit if I can.


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## Salvatoreg02 (Feb 26, 2011)

I happen to agree the conduit acts better as a EGC, provide it is installed correctly. I believe the NEC has a section that determines the ampacity characteristics of all size conduits?


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## McClary’s Electrical (Feb 21, 2009)

Salvatoreg02 said:


> I believe the NEC has a section that determines the ampacity characteristics of all size conduits?


 
nope


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## Big John (May 23, 2010)

BBQ said:


> So in a wooden building wired with either NM or PVC would you run two independent EGCs because all it takes is one bad EGC splice and you have no EGC?


 No, because I don't look at this as a workmanship issue. 

I simply think it's more likely for other trades to damage EMT and still leave the internal wiring intact than it is for them to damage an equipment ground wire.

That being said, I've run EMT as the the equipment ground, and I've done it in wooden buildings. I still think it's an inferior method.

As an aside, I took a look through Soares last night to re-read that test on fault current paths. The conclusion was not that conduit was a vastly superior EGC when compared to an internal ground wire, only that it was important to bond conduit where present, and that relying on external conductors was a bad idea: 

At low currents of several hundred amps, the internal ground actually carried the majority of the current. At currents of about 10kA for a 1/4 second, it was split between conduit and wire by about 50/50.

-John


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## 480sparky (Sep 20, 2007)

Salvatoreg02 said:


> I happen to agree the conduit acts better as a EGC, provide it is installed correctly. I believe the NEC has a section that determines the ampacity characteristics of all size conduits?


That would be Soares.


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## Amish Electrician (Jan 2, 2010)

I often find local ammendment that require one, at least in certain locations (such as rooftops). 

My personal view: I'm quite comfortable with the pipe as my ground for branch circuits. I'll use a wire for feeders. Whether this is a code requirement is not clear.

For feeders, code says you'll size the EGC according to a table - a table that does not mention steel pipe as one of the conductor choices. 

As an extreme, I just looked at a panel where the sparky not only put every receptacle in its' own breaker, but he also pulled a separate green wire to each one. (There were NOT isolated ground devices, and RMC was the method).


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## BBQ (Nov 16, 2010)

Big John said:


> No, because I don't look at this as a workmanship issue.
> 
> I simply think it's more likely for other trades to damage EMT and still leave the internal wiring intact than it is for them to damage an equipment ground wire.


Pretty selective reasoning John, if I am following you look at it like this ...

Trades will damage conduit but not cable.

People will run pipe sloppy but make perfect splices.


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## 10492 (Jan 4, 2010)

I run ground wires, for peace of mind, in conduit even if not required.


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## Big John (May 23, 2010)

BBQ said:


> ...Trades will damage conduit but not cable.....


 Just basing it on my experience, which suggests that, yes, conduit does seem to get damaged more than grounds get broken.

But, I will grant that separated conduit is easily visible, wheras a broken ground wire often will not be without opening boxes.

-John


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## Wirenuting (Sep 12, 2010)

I run conduit all the time, I pull a ground only when I believe it might be needed or is required. 

But this weekend I ran romex for the first time in all these years. A bunch of 14/2 for sconce & picture lights for my wife. What a PITA that was. The attic was like an oven and I hit every nail in the sill plates. 
Since it was in my own house, I locked the door and pulled the shades so no one would see me running rope.


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## BBQ (Nov 16, 2010)

Wirenuting said:


> I locked the door and pulled the shades so no one would see me running rope.



You can't hide the shame from yourself. :laughing:


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## B4T (Feb 10, 2009)

The building steel is grounded just by the construction footings.. plus you have mechanical fasteners on the EMT.. connected to the building steel.. before and after the separated coupling..

So the ground path is still continuous or am I missing the point here.. :blink:


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## Wirenuting (Sep 12, 2010)

BBQ said:


> You can't hide the shame from yourself. :laughing:


I think I should have hide behind a troll screen name. LoL


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## Amish Electrician (Jan 2, 2010)

Yes, B4T, you missed something. Don't feel bad, it's an easy goof.

The 'ground' we're worried about has nothing at all to do with the Mother Nature, the building footing, etc. No, all we're concerned with is an extremely good path back to the panel, so the breaker will trip when there's a fault.

UL did a study, which showed remarkably good performance of even poorly connected conduit as a fault path. Much of the information can be found at the website for the Steel Tube Institute.


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## RIVETER (Sep 26, 2009)

Wireman191 said:


> Ever had to go fix a broken conduit and grab one end, then the other and get the living crap zapped out of you... not a good feeling.:no:


Most likely, what you experienced was a conduit system with a bare neutral. That can kill.


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## McClary’s Electrical (Feb 21, 2009)

RIVETER said:


> Most likely, what you experienced was a conduit system with a bare neutral. That can kill.


 
As long as the neutral was landed on both ends he would not feel that. It was far more likely an actual phase to ground fault downstream of the broken conduit.


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## B4T (Feb 10, 2009)

Amish Electrician said:


> Yes, B4T, you missed something. Don't feel bad, it's an easy goof.
> 
> The 'ground' we're worried about has nothing at all to do with the Mother Nature, the building footing, etc. No, all we're concerned with is an extremely good path back to the panel, so the breaker will trip when there's a fault.
> 
> UL did a study, which showed remarkably good performance of even poorly connected conduit as a fault path. Much of the information can be found at the website for the Steel Tube Institute.


You still have steel connected to steel.. the ground path is still continuous around the broken coupling.. the fault path trips the breaker.. yes or no.. :blink:


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## 480sparky (Sep 20, 2007)

RIVETER said:


> Most likely, what you experienced was a conduit system with a bare neutral. That can kill.



Most likely, it was a conduit system that was no longer bonded and became energized just through the magnetic field of the conductors it enclosed.


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## McClary’s Electrical (Feb 21, 2009)

B4T said:


> You still have steel connected to steel.. the ground path is still continuous around the broken coupling.. the fault path trips the breaker.. yes or no.. :blink:


 
In theory you are correct. However we're not allowed to count things like tin and painted rediron with bolt connections to carrry fault current.


*Effective Ground-Fault Current Path.​*​​​​An intentionally
constructed, low-impedance electrically conductive path
designed and intended to carry current under ground-fault
conditions from the point of a ground fault on a wiring system
to the electrical supply source and that facilitates the operation
of the overcurrent protective device or ground-fault detectors​
on high-impedance grounded systems.


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## McClary’s Electrical (Feb 21, 2009)

480sparky said:


> Most likely, it was a conduit system that was no longer bonded and became energized just through the magnetic field of the conductors it enclosed.


 

:laughing::laughing::laughing::laughing::no:


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## 480sparky (Sep 20, 2007)

mcclary's electrical said:


> :laughing::laughing::laughing::laughing::no:



Uh, how is electricity created by a generator? :whistling2:


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## B4T (Feb 10, 2009)

mcclary's electrical said:


> In theory you are correct. However we're not allowed to count things like tin and painted rediron with bolt connections to carrry fault current.
> 
> That part I know.. it was just the separated coupling I was talking about.. it is not as bad as it looks... all I am saying..


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## RIVETER (Sep 26, 2009)

480sparky said:


> Most likely, it was a conduit system that was no longer bonded and became energized just through the magnetic field of the conductors it enclosed.


You have got to be kidding.


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## McClary’s Electrical (Feb 21, 2009)

480sparky said:


> Uh, how is electricity created by a generator? :whistling2:


 
MANY different ways. But none of which include energizing wires that are passing through a metal tube, and then collecting said current supposedly induced on the tube by the wires, and then selling what is produced by the tube. I think you're joking, or maybe you've faked your entire understanding of electricity.:yes:


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## Big John (May 23, 2010)

480sparky said:


> Most likely, it was a conduit system that was no longer bonded and became energized just through the magnetic field of the conductors it enclosed.


 I could see some sort of induction if there was no neutral, either, to cancel the the field. I'm thinking it'd have to be a pretty long piece of conduit before you could feel it, though.

-John


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## 480sparky (Sep 20, 2007)

mcclary's electrical said:


> MANY different ways. But none of which include energizing wires that are passing through a metal tube, and then collecting said current supposedly induced on the tube by the wires, and then selling what is produced by the tube. I think you're joking, or maybe you've faked your entire understanding of electricity.:yes:



You're missing the basics..... it's done by passing a magnetic field through a conductor.

And that's exactly what energized wires inside an ungrounded EMT do.

This is first-year stuff.



Ever notice line crews grounding cables that are near other energized cables? That's so the don't build up a charge.


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## McClary’s Electrical (Feb 21, 2009)

480sparky said:


> You're missing the basics..... it's done by passing a magnetic field through a conductor.
> 
> And that's exactly what energized wires inside an ungrounded EMT do.
> 
> ...


So you're comparing high voltage work to induction caused by circuits under 600 volts?? Totally different animal, and the reason the are grounding those wires is not induction. 

I maintain that you could never ever ever ever flow enough current on wires that are going through conduit to induce a charge on the conduit high enough to knock the piss out of somebody, let alone even feel it. Hell, I'd bet you don't have anything sensitive enough to measure it.


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## 480sparky (Sep 20, 2007)

mcclary's electrical said:


> So you're comparing high voltage work to induction caused by circuits under 600 volts?? Totally different animal, and the reason the are grounding those wires is not induction.
> 
> I maintain that you could never ever ever ever flow enough current on wires that are going through conduit to induce a charge on the conduit high enough to knock the piss out of somebody, let alone even feel it. Hell, I'd bet you don't have anything sensitive enough to measure it.



Induction is induction. Voltage is not relevant. Cripes, this is how _transformers_ work!

And you are incorrect. I've been hit by a charge built up in ungrounded conduits.

An ordinary voltmeter is all you need.


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## BBQ (Nov 16, 2010)

480sparky said:


> Induction is induction. Voltage is not relevant.
> 
> And you are incorrect. I've been hit by a charge built up in ungrounded conduits.


Fibber.


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## McClary’s Electrical (Feb 21, 2009)

480sparky said:


> Induction is induction. Voltage is not relevant. Cripes, this is how transformers work!
> 
> And you are incorrect. I've been hit by a charge built up in ungrounded conduits.
> 
> An ordinary voltmeter is all you need.


Yep, that's how transformers work. Thousands and thousands of feet of wire coiled up in order to create a magnetic field. Single insated conductors passing through a conduit are not gonna produce a magnetic field strong enough to induce any measurable voltage.


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## 480sparky (Sep 20, 2007)

mcclary's electrical said:


> Yep, that's how transformers work. Thousands and thousands of feet of wire coiled up in order to create a magnetic field. Single insated conductors passing through a conduit are not gonna produce a magnetic field strong enough to induce any measurable voltage.



Wanna bet? I'm more than happy to take your money.



mcclary's electrical said:


> ......... Hell, I'd bet you don't have anything sensitive enough to measure it.


Ten bucks?

A hundred bucks?


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## BBQ (Nov 16, 2010)

I believe induction requires a complete circuit.

http://en.wikipedia.org/wiki/Faraday's_law_of_induction

I further believe what you are trying to describe is capacitance coupling.

http://www.electrical-installation.org/enwiki/Capacitive_coupling


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## 480sparky (Sep 20, 2007)

BBQ said:


> I believe induction requires a complete circuit.
> 
> http://en.wikipedia.org/wiki/Faraday's_law_of_induction
> 
> ...



I Photoshopped that web site just for you. :jester:


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## BBQ (Nov 16, 2010)

480sparky said:


> I Photoshopped that web site just for you. :jester:




LMAO, great job.


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## 480sparky (Sep 20, 2007)

C'mon.... bet me. I want some money! :yes:


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## don_resqcapt19 (Jul 18, 2010)

480sparky said:


> You're missing the basics..... it's done by passing a magnetic field through a conductor.
> 
> And that's exactly what energized wires inside an ungrounded EMT do.
> 
> This is first-year stuff.


But there is little magnetic field with a correctly installed circuit. You will have all of the conductors of the circuit in the raceways and the fields tend to cancel out. There will be some, but I would be very surprised if there was enough to create a voltage that you could feel. 



> Ever notice line crews grounding cables that are near other energized cables? That's so the don't build up a charge.


Prat of that charge build up is from wind produced static.


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## 480sparky (Sep 20, 2007)

don_resqcapt19 said:


> ...... but I would be very surprised if there was enough to create a voltage that you could feel. ...........



I've felt it all right..... put me on my ass.

Bin dere, dun dat.


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## McClary’s Electrical (Feb 21, 2009)

480sparky said:


> I've felt it all right..... put me on my ass.
> 
> Bin dere, dun dat.


There was a fault in the circuit grounded to the conduit. What you are stating is impossible. Even if there was enough coupling to get a very small reading with a dmm, as soon as you touch it, it would go to zero. There's not enough current to shock somebody. If there were, every conduit would be a potentially open neutral. If you still maintain you were shocked hard enough to knock you down, from an isolated conduit that was charged magnetically from the conductors it contained, I will forever and ever from this point out consider you a liar.


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## 480sparky (Sep 20, 2007)

mcclary's electrical said:


> There was a fault in the circuit grounded to the conduit. What you are stating is impossible. Even if there was enough coupling to get a very small reading with a dmm, as soon as you touch it, it would go to zero. There's not enough current to shock somebody. If there were, every conduit would be a potentially open neutral. If you still maintain you were shocked hard enough to knock you down, from an isolated conduit that was charged magnetically from the conductors it contained, I will forever and ever from this point out consider you a liar.


Funny how you know all the circumstances _even though you were never there._

There was NO fault.... just energized wires inside some EMT that had yet to be grounded. Came back the next day, grabbed a box while kneeling on damp grass and went ass over elbows.

Continue to maintain it never happened if you wish. But it did.


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## McClary’s Electrical (Feb 21, 2009)

480sparky said:


> Funny how you know all the circumstances even though you were never there.
> 
> There was NO fault.... just energized wires inside some EMT that had yet to be grounded.


Which would not produce CURRENT to shock you. Even if you saw some small voltage with a DMM, it's only ghost voltage. Just like reading power on the red wire of 14/3, even when it's disconnected on both ends. I guess that will knock the piss out of you too?


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## McClary’s Electrical (Feb 21, 2009)

480sparky said:


> Funny how you know all the circumstances even though you were never there.
> 
> .


That's the only circumstance that's keeping you from looking like a looney tune right now.


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## 480sparky (Sep 20, 2007)

mcclary's electrical said:


> Which would not produce CURRENT to shock you. .........



Funny how there WAS.


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## RePhase277 (Feb 5, 2008)

480sparky said:


> Funny how there WAS.


Ken, I love your posts and almost never disagree with you, but what you are saying is inconsistent with the laws of physics. A conductive tube surrounding a conductor would have a current induced in it that flowed RADIALLY around tube, not axially along the tube. 

Besides that, that induced radial current would have no ground reference, so kneeling down on the dirt would have no effect on it. The fact that it happened AFTER you touched the grounded dirt leads me to believe that the voltage that caused the shock came from either the system you were working on, or from another grounded system that found a path through that pipe.

And besides THAT, an open circuit conductor would induce no current. Current must flow for current to be induced. And rarely is there just ONE conductor in a pipe, so most circuits have EM fields that are balanced and net zero.


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## McClary’s Electrical (Feb 21, 2009)

480sparky said:


> funny how there was.


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## pistol pete (Jul 4, 2011)

Wet grass and fresh emt ? Really?


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## 480sparky (Sep 20, 2007)

pistol pete said:


> Wet grass and fresh emt ? Really?


Wow. I guess updating a detached garage is physically impossible as well.


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## 480sparky (Sep 20, 2007)

InPhase277 said:


> ..............
> And besides THAT, an open circuit conductor would induce no current. Current must flow for current to be induced. And rarely is there just ONE conductor in a pipe, so most circuits have EM fields that are balanced and net zero.


I'm sorry. Where did I say there was no current flow on the wires?


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## guest (Feb 21, 2009)

Ken, what were the EXACT conditions at the time? For example:



Length of conduit run, TOTAL
Length of conduit run section that bit you
Size and number of conductors in the conduit that bit you
Single 120v circuit, MWBC, or 120/240 feeder
Actual current at the load end of those conductors
EGC or no EGC
Conduit connected to a grounded box/panel yes or no (answer for both ends)
Did you measure the voltage to ground on the "bite pipe" and what was it?
Reason I am asking is because if it is practical to do so I want to duplicate the setup and do some testing. I am also of the camp that unless you were dealing with thousands of volts or thousands of feet of EMT there is no way enough current can be induced in the EMT to knock you on your azz. 



Honestly, my money is on a nick in a hot conductor that energized the pipe. I had a BRAND NEW roll of THHN (black) that had several nicks in the insulation throughout 100 feet or so of the roll. And I seem to recall someone posting pics of defective THHN where there were random strands poking through the insulation. 



Another likely scenario: How close are the POCO lines to your house or the jobsite in question? You could have easily been hit by HV earth return path current, or even the return current of a neighbor's lost neutral coming back through your grounding electrode system.


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## 480sparky (Sep 20, 2007)

Cripes, it was years ago.

But here's the whole story:

Customer had an older detached garage... one light, a couple receps, and all exposed ungrounded NM. So I piped in new lights, switches, receps, etc. All was going to be refed since the existing UF was ungrounded. 

I spent one day piping it all, and running everything back to a bell box on the outside of the garage. To fire it all up, I turned off the existing UF in the house, and moved it into my new bell box. I turned it back on so their door opener would work.

Came back the next day, dug the trench in to refeed the garage. When I was kneeling down on the wet grass, I grabbed the bell box and got sent packin' across the yard. I measured 121 volts to the ground in my new UF feed before I cut the old feed off.

There was NO SHORTS, NO NICKS, NO GROUND FAULTS because I hooked up the new UF and nothing tripped and the EMT was no longer energized.......... because it was _now grounded_.


I have no idea what the loads were during the interim, maybe 150' of pipe total. I did run a ground wire, but it wasn't hooked to anything until I hooked up the new UF feed.


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## chicken steve (Mar 22, 2011)

we pulled multiple copper conductors almost 1/4 mile on one job

the few that were energized made it impossible to work the ones that were not 

induction happens, it's simply a matter of magnitude

~CS~


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## BBQ (Nov 16, 2010)

chicken steve said:


> we pulled multiple copper conductors almost 1/4 mile on one job
> 
> the few that were energized made it impossible to work the ones that were not
> 
> ...


Not induction with open circuits, it is not possible. 

Capacitance coupling.


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## BBQ (Nov 16, 2010)

A little info on it

http://www.nema.org/prod/wire/build/upload/Bulletin 88 2003.doc


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## mdfriday (May 14, 2007)

480sparky said:


> Cripes, it was years ago.
> 
> But here's the whole story:
> 
> ...



Garage door opener motor....

Ever take off a receptacle with garvin cover (exposed work cover) with no bonding strap, and for instance a sump pump plugged in to it....even when not running I measured 80V from cover to metal box / emt when it was not screwed to the box..... installed bonding strap, no more potential (voltage)......

That laid me out in a crawl space once....


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## Amish Electrician (Jan 2, 2010)

B4T ... and others not clear on the concept .... the ground rod, the grounding electrode conductor, and the dirt under your feet have absolutely nothing to do with clearing faults.

Proof? NEC allows the ground resistance to be 25 ohms. Imagine a dead short to ground on a 120 circuit. How many amps will it draw? Ohms law. V=IR. 120= I (25 ohms). That's less than 5 amps. When do you think that 20-amp breaker will trip?

Proof? Code specifically says we will not use the earth as a conductor.

More proof? We're required to run ALL conductors in the same raceway. Let's see you put the dirt you're standing on in that pipe ....

Nope, you need a low-impedence path all the way back to the transformer for the breaker to trip. Conduit, being bonded to the neutral via the panel case, qualifies.

How well does it qualify? Read the studies. Adding a wire to the conduit often does nothing to improve the 'ground.'

I still want to meet the 'electrician' who ran those FIVE ground wires in the pipe I worked on yesterday (to serve seven 20-amp circuits).


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## 10492 (Jan 4, 2010)

pistol pete said:


> Wet grass and fresh emt ? Really?



:laughing:

Too funny........


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## Big John (May 23, 2010)

I will say I've seen a similar circumstance to the one 480 describes: 

Doing trimout checks and an apprentice tells me a GFCI doesn't work and he's reading 120V on both hot an neutral.

Take out the receptacle and sure enough, voltage on both hot and neutral. When I put a tester on the neutral I saw it drop a couple volts. So on a hunch, I had the kid put his tester on too, and it dropped down below 100 volts.

Turned out to be the neutral was never connected on the other end, and was running through a conduit for several hundred feet with a whole bunch of other CCCs, and what we were seeing was nothing but coupled voltage. This was the worst case of "phantom voltage" I've ever seen though, because even with a ground path of a few thousand ohms, it didn't null the voltage out completely.

-John


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## McClary’s Electrical (Feb 21, 2009)

Big John said:


> I will say I've seen a similar circumstance to the one 480 describes:
> 
> Doing trimout checks and an apprentice tells me a GFCI doesn't work and he's reading 120V on both hot an neutral.
> 
> ...


An open energized neutral will always read 120 volts to ground. These situations are not similar, unless I'm misunderstanding you.you


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