# Grounding question



## Magnettica (Jan 23, 2007)

If it's connected to the electrical supply source in a manner that establishes an effective groundfault current path I do not see any issues.

250.4(A)(4)


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## Pete m. (Nov 19, 2011)

Magnettica said:


> If it's connected to the electrical supply source in a manner that establishes an effective groundfault current path I do not see any issues.
> 
> 250.4(A)(4)


I suppose that's the point of the question. Would the 6-32 screw provide enough pressure on the lug to assure adequate surface contact to comply with 250.4(A)(5).

Pete


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## Magnettica (Jan 23, 2007)

Then that would be up to the AHJ and their interpretation of the code.


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## Barjack (Mar 28, 2010)

It doesn't seem like a good idea, but I can't find anything that specifically prohibits such a small screw on such a large wire, as long as it engages at least 2 threads. 

I think you could site 110.12, as I don't think there is any way you could mechanically maintain the connection of a 3/0 copper conductor with just a 6-32 screw. As soon as that conductor is bumped or moved it would loosen. 


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

It needs to be listed. I've never seen a6/32 listed for grounding.


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## Dennis Alwon (May 9, 2009)

I don't see anything in 250.8 that says it must be listed nor anything that says what size as long as it catches 2 screws. My bet is it is a sucky connection and I wouldn't do it but not sure one can turn it down


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## chicken steve (Mar 22, 2011)

Wouldn't the 6-32_ theoretically _need a 7200AIC rating....?

~CS~


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

Dennis Alwon said:


> I don't see anything in 250.8 that says it must be listed nor anything that says what size as long as it catches 2 screws. My bet is it is a sucky connection and I wouldn't do it but not sure one can turn it down


I'm not quoting 250.8 I'm quoting 250.148 (c)


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## chicken steve (Mar 22, 2011)

One would think a 6-32 would fall right through a 3/0 lug.....

~CS~


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## Carultch (May 14, 2013)

Vascarelli said:


> You would use a washer.


Would the washer need a listed connection between its surface and the lug surface? As well as a listed connection from it to its fastener head?


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

Carultch said:


> Would the washer need a listed connection between its surface and the lug surface? As well as a listed connection from it to its fastener head?


I dunno. What does the verbage say? 



C) Metal Boxes. A connection shall be made between the one or more equipment grounding conductors and a metal box by means of a grounding screw that shall be used for no other purpose, equipment listed for grounding, or a listed grounding device.


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## don_resqcapt19 (Jul 18, 2010)

If I am the inspector you get a red tag if the bolt used is more than on size smaller than the hole in the lug.

However I don't have anything to support that. I would expect that the lug is tested using a bolt the same size as the hole in the lug, so it is likely a 110.3(B) issue.

If you fight me, I am sure that there are many other violations in your job, if I go through it with a fine tooth comb


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## don_resqcapt19 (Jul 18, 2010)

mcclary's electrical said:


> It needs to be listed. I've never seen a6/32 listed for grounding.


250.148 does not require that the screw be listed for grounding.


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## 360max (Jun 10, 2011)

don_resqcapt19 said:


> 250.148 does not require that the screw be listed for grounding.


it may fall under the requirement by the lug manfacture


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

don_resqcapt19 said:


> 250.148 does not require that the screw be listed for grounding.


Technically no, but you need to realize one thing. 


You are in the wrong business. You should have been a public defender. I mean this with all my heart. 

You keep reading the nec from a lawyers perspective, there's one great big huge problem with this, you're not a lawyer, 100% of inspectors are not lawyers, and 100% of ahjs are not lawyers. You're like Bill Clinton asking " it depends on what the meaning of is, is? " 

You take it entirely a step too far, and refuse to admit the code was written for us to understand. 

So yes, I admit it doesn't say the screw shall be listed. But it does say the screw shall be listed if used by itsself. So how if that possible? How can I use a listed screw and only a listed screw , by itself? Please explain how. You cant. It's not possible. 

I'll save you the time,it is not possible, so I must move on to the second option, using a listed grounding product. Funny thing is, I buy literally thousands of listed ground lugs, (get this) without screws. (Gasp) imagine that? A listed product without a listed screw, when the very sentence before that in the code demands a listed screw. How can that be? 

I have to use a listed product (a)

If not move on to a listed product (b)


Uh oh, product (b) didn't come with product ( a) ....... does that mean I can use whatever the hell I want? If you only consider the verbage, yes. If you consider common sense, and the fact that the code is not written by lawyers for lawyers, then (common sense) would tell you no. 



You need to start visiting lawyers forums and stay off this one. Seriously.


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

Vascarelli said:


> Can you wrap a number 14 wire around a ground screw tapped into the side of a panel? Wouldn't that be a way to use a listed screw by itself?


How are you gonna tap a #14 to a 3/0 egc?


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## Semi-Ret Electrician (Nov 10, 2011)

Pete m. said:


> This is hypothetical and only for discussion.
> 
> If I had a 1200 amp feeder with a 3/0 EGC would it be code compliant to use a 6-32 screw to attach a lug to the panelboard enclosure for the EGC as long as the wall of the panelboard was at least 1/16 of an inch thick?
> 
> Pete


 Pete I asked a similar question at a recent SOARES seminar:

How can a steel 6-32 screw carry the current of a 1/4" CU?

The answer was it's legal but doesn't seem right.

I guess if the paint on the panel is removed, the bulk of the fault current is carried through the lug to panel contact, not the green screw.


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## Carultch (May 14, 2013)

Semi-Ret Electrician said:


> I guess if the paint on the panel is removed, the bulk of the fault current is carried through the lug to panel contact, not the green screw.


Is panelboard paint an insulator or a conductor?


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## Semi-Ret Electrician (Nov 10, 2011)

Carultch said:


> Is panelboard paint an insulator or a conductor?


 Insulator, should be removed at the bonding screw location


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## don_resqcapt19 (Jul 18, 2010)

mcclary's electrical said:


> Technically no, but you need to realize one thing.
> 
> 
> You are in the wrong business. You should have been a public defender. I mean this with all my heart.
> ...


You can say it how every you want to, but a 10-32 screw is a 10-32 screw. There is no requirement to use a green 10-32 screw for grounding connection. I don't think that there is even an UL Standard that a grounding screw can be listed to.

The code is not written for the users, it is written to be a legally enforceable document. It is far from being user friendly.


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## pete87 (Oct 22, 2012)

Screw must be Green ?




Pete


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## Pete m. (Nov 19, 2011)

don_resqcapt19 said:


> If I am the inspector you get a red tag if the bolt used is more than on size smaller than the hole in the lug.
> 
> However I don't have anything to support that. I would expect that the lug is tested using a bolt the same size as the hole in the lug, so it is likely a 110.3(B) issue.
> 
> If you fight me, I am sure that there are many other violations in your job, if I go through it with a fine tooth comb


If faced with an install that I made up I would attempt to cite 250.4(A)(5).

I would have no scientific basis nor would I be able to prove that the connection utilizing the 6-32 didn't provide an adequate fault return path but man I would sure hate to just pass it without question.

Pete


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## don_resqcapt19 (Jul 18, 2010)

pete87 said:


> Screw must be Green ?
> 
> 
> 
> ...


 Only on a wiring device. Not anywhere else.


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## dronai (Apr 11, 2011)

Pete m. said:


> If faced with an install that I made up I would attempt to cite 250.4(A)(5).
> 
> I would have no scientific basis nor would I be able to prove that the connection utilizing the 6-32 didn't provide an adequate fault return path but man I would sure hate to just pass it without question.
> 
> Pete


 You should fail this installation based on common sense.


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## Barjack (Mar 28, 2010)

Can a lug sized for 3/0 be adequately secured to a box with a 6-32? I just don't see how…


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## Pete m. (Nov 19, 2011)

Barjack said:


> Can a lug sized for 3/0 be adequately secured to a box with a 6-32? I just don't see how…
> 
> 
> Sent from my iPhone using electriciantalk.com


I would assume washers would have to come into play.

Pete


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## don_resqcapt19 (Jul 18, 2010)

dronai said:


> You should fail this installation based on common sense.


 I can't find a section on common sense in the NEC


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## Hawkrod (Mar 19, 2012)

Pete m. said:


> I would assume washers would have to come into play.
> 
> Pete


Would those be listed washers? :whistling2:


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## Hawkrod (Mar 19, 2012)

don_resqcapt19 said:


> I can't find a section on common sense in the NEC


That section was delisted some time ago!


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## Pete m. (Nov 19, 2011)

Hawkrod said:


> Would those be listed washers? :whistling2:


But of course!:jester::no:

Pete


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