ECN Forum Forums Code Related Discussion NEC & other Code issues Need opinion

I have boxes of 'ground screws' and they are not UL Listed, if anyone can find some UL Listed ground screws please post the info.

Bob

If we continue to insist that 250.8 requires listed grounding screws a few things come to mind, which have been mentioned before.

1)There would be no need to specifically say:

"Sheet metal screws shall not be used to connect grounding conductors to enclosures."

2)As I can not find UL listed 'grounding screws' the use of the green ground screws is as much a violation as using the clamp screws.

This (as Don pointed out) leaves us with the only listed product for the job being a 'grounding clip' and it in no way provides as secure connection as a machine screw.

3)We all clearly know that we can use a unlisted nut and bolt to connect wire terminals of ungrounded, grounded and grounding conductors.

I can say that the AHJ in the States I work accepts standard machine screws to bond a device box.

Bob

[This message has been edited by iwire (edited 05-22-2004).]

walrus,
Note that the wording saying "identified for the purpose" is in a panel members negative comment on the panel action. The official panel statement is "Section 110-14(a) does not permit the connection of a solid conductor with an ordinary machine screw." It appears that the panel is only taking issue with the termination of a conductor directly with a screw and that there is no objection to the use of screws and bolts to terminate lugs and similar devices.
Don

Don
It is your turn to file a request for formal interpretation in order to make the CMP face the music.

The question would read something like "Does section 110-14(a) require that the screw used to connect the Equipment Grounding Conductor to a device box be listed for the purpose?"
--
Tom Horne

I think George Little is correct.

Look at the screws on devices, if he is wrong and any machine screw is suitable for grounding we could replace screws on devices with machine screws and claim code compliance. I think that is a violation of the devices listing.

This all comes down to whose opinion is regarded not who is right.

As an inspector or contractor I would make public what "proof" I would supply or accept. I guesss I would accept as proof I was wrong either the NEC code commentary or the ROCs. I would also accept a written statement (accepting liability) from a Licensed engineer.

Green screws or machine screws is not a big issue. You work small issues out and get on with your work. Being right is too expensive.

Quote from Joe T's post:

Howdy:
It just so happens that UL agrees with those of us here who have not accepted the clamp screw threaded hole for the termination of the "Equipment Grounding Conductor" or "Pigtail Equipment Bonding Jumper."

How many of you will come back and say: "You were right"?

Qualify this statement and I will be one of the first to say you are correct. Don has been very diligent to research the facts concerning this debate and disclose his findings whether they support his position or not. I think it is only fair to expect the same from Yooper or Joe. It has been determined that Raco, Appleton, Thepitt and Steel City have UL listed 1 gang device boxes on the market with tapped holes that have no markings identifying them for a specific purpose. I would really like to know the complete correct answer to this debate. Please don't throw a bomb. Offer UL listing info or NEC reference to support such statements as the one quoted above.

George, this has nothing to do with devices. that issue is pretty clearly spelled out in the NEC and device listings.

George, this is part of the problem. Read 406.9 (B)(1) and notice the NEC took time to specify this because it was the intent that on a device all terminals are identified.

Also note the wording not readily removeable

If the NEC intended the same identification for the connection to an outlet box, they would have included wording somewhere to mandate this,

They could also mandate that the boxes would have a not readily removeable green screw installed from the factory, but this is not the case.

Edited to correct a spelling error.

Roger



[This message has been edited by Roger (edited 05-22-2004).]

Dom
I understood that(sorry for any confusion), my point was, it appears this panel member was asking for a green screw. I figure a green screw is identified for the purpose. Maybe I'm being too simplistic.

I want to add that is a great discussion, on most boards it would have been locked by now as the flames would have been out of control . Picking the brains of folks who are more knowledgeable is a great way to learn.

walrus,
I agree that it appears that the panel member was asking for a green screw, but "identified for the purpose" is another murky area of the code.
It does not come right out and require a listed product, but only says in the FPN that a listing is one way to "identity for the purpose".

I still see no electrical reason why a standard machine screw cannot be used in any threaded hole in the box for the termination of the EGC. I'd be willing to bet that if you used a micro-ohm meter that any type of machine screw would show less connection resistance than the listed push-on clamp device and that there would no difference in the readings between the green screw, the cpamp screw or a hardware store machine screw.
Don