I have a Contractor who maintains that an acceptable way of bonding/grounding a metal box used in a NM cable installation, would be to wrap the bare equipment ground wire around the screw that is used with the cable clamp. Now there are no cables under the clamp and the clamp is still installed so the bare wire is under the head of the screw and between the screw head and the clamp. I maintain that the Contractor should be using the 8-32 hole provided for installing a GREEN screw and not use the cable clamp screw what-so-ever for grounding. I don't think he should even use the silver colored cable clamp screw in the hole provided for the GREEN ground screw. I need something official for a reference. Thank You in advanc.

George
Look at 250.148A

George also 314.40D

There is no code rule that requires the use of a "green" screw for the connection of the EGC. The use of the clamp screw with the clamp still installed would be a violation of 250.148(A), but there is no violation if the clamp is removed and the clamp screw is used to connect the EGC.
Don

250.148A says a GROUNDING screw used for NO other purpose! A box clamp screw is Not a Grounding screw. For one thing the head is usually to small and the wire tends to slip out when tightened.

Yoopersup: I concur with Don. What is to prevent you from using a Sta-Con from satisfying your dilemna?

...Now there are no cables under the clamp and the clamp is still installed so the bare wire is under the head of the screw and between the screw head and the clamp.

Why the heck would you leave an unused clamp in the box anyway? Not only would it prevent the screw from being firmly tightened on the ground wire and is a violation of 250.148(A) but it counts as a conductor in calculating box fill.

Dunno, but whenever I see unused clamps still in place it screems DIY!

-Hal

I agree with Don and Ryan. There is no definition of a ground screw in the NEC. The usual mentioning of a green hex head screw is for devices 250 126. Yoopersup has provided two good references.

Pierre

Yoopersup,
Please show me the NEC definition of a "grounding screw".
Don

I believe there is no UL listing for ground screws only.

The only UL Listed screw items I have ever seen are a combination of screw and wire pig tail.

Read 250.8 2002 handbook. Also explains, Listed clamps or other Listed means. Shows pic of 4" square box with Listed ground screw. cable clamp box screw is Not a Gr, screw.Page 178 2002 NFPA code handbook.Now if thread correct you could use threaded hole to intall a Proper gr screw.

The handbook is not code and there is no code requirement to use a green screw. What do you do for a 250kcmil, connect the lug to the bus using a green 10-32 grounding screw???????? The only code restriction on the type of screw used for a grounding connection is that it must not be a sheet metal screw. The only other restriction is that the screw cannot serve any other purpose.
Don

Morning Don
Ist the NEC code HANDbook is put out by the NFPA same folks whom bring us the code book. Its interpreations are accepted by most electrical inspectors, Two. Now you know a 250kmcm won;t fit under a 10/32 you:d be Required to use a LISTED and LABELED lug approved for that purpose.
Also in your area if its APPROVED by the AHJ (look up def of approved) You I suppose could do it. I just think Code says no and if you:ve ever put a ground screw under a cable clamp you:d know it tends to slip out as tightened because the head is so small. Ground screw have much larger heads.
Hope I started your day in a good mood. )

Yoopersup,
My point is that if you say that the screw that is used for the termination of the EGC must be a listed "green grounding screrw" there is no way to terminate the listed and labled lug used on a large conductor to the enclosure or grounding bus.
The interpreations in the code handbook are not the offical position of the NFPA and are no more valid than yours or mine.
The code does not intend that the only screw that can be used to terminate an EGC is the green 10-32 screw. Can you provide the UL listing category for a "grounding screw"? I haven't been able to find it.
Don

Have you ever attached a lug for a 3/0 to the building steel by using a 10/32? Of course not, you use a 1/4x20. Thats because it just doesn't matter. A screw is a screw, as long as it is not a sheet metal screw.

I thought the Subject was Metal boxes ?? When did we get off on lugs to steel ect.If you feel a cable clamp screw well do the Job by all means Go for it BUT like I said try it some time you:ll see what I mean. As Far as the NEC Code handbook I feel its interpretations as as good as any you:ll find.Several of people who had a hand in the handbook are on the code panels. No hard feelings been fun sparing with you time to move on.

Boy you guy sure get testy when someone challenges you. Wish I had not brought it up. After seeing the comments and the counter comments I have concluded that if you are using NM cable and it contains a gouunding conductor ir can be bonded to the box by a screw of any discription and if it is a a ground screw that purchased at the supply house it probably will be green. Nothing in the code book requires it to be listed. So we are talking about a judgment call as to whether it is effectively bonded. So now let's talk about the fact that there are no requirements for anything to be UL listed. Or, lets talk about whether the jumper to the box for our NM cable installation is a bonding conductor or a grounding conductor. By the way, I miss spoke the situation, the screw is a 10/32 not an 8/32

Your right, the topic is metal boxes. Lets say we've got a 24"X24" J-box with 350's in it. How are you going to terminate the equipment ground to the box?

Ryan- assume NMRC and a metal box, I'd use a piece of #4 (identified with green tape) and a lug Listed for the conductor material and a bolt and nut. More than likely the bolt, nut and lug won't be green. But that has nothing to do with the oringinal question :-/

O.K. guys, I am going to pick your brains for a second or two.
Back in 93 or 96 code cycle, Elect. contractor Mag. put out a booklet of code changes,(which they still do), about the ground screw and bonding screw in panel boards had to be green and of the threaded type, and it could not be a sheet metal or tek screw.
Anyone else recall this? I cannot find My 2002 handbook to look it up cuz I moved, but my wife has seen it. Just my .02 cents!

Zapped,
You are talking about two different rules. If the main bonding jumper in the service equipment is a screw, that screw must have a green head. See 250.28(B). The purpose of this rule was to make it easier for the inspector to see if the main bonding jumper was installed. The other rule in 250.8 prohibits the use of a "sheet metal screw" to connect a grounding conductor to an enclosure. The only problem with this rule is no one knows what a "sheet metal screw" is.
Don

Not permitted! Absolutely not!

I never would allow the cable clamp threaded hole to be used for the termination of the EGC or EBJ!

Listed products identify that hole in metal boxes with "GR" or "GRND" and one regular reference is 110.3(B)!

Joe, the intent is to be sure that at lease two threads are fully engaged. In the case of standard boxes, it makes no difference which hole is used as long as it used for no other purpose (you will find nothing in the Code or the UL White Book that prohibits this practice). Additionally, the guys from the NFPA do not serve on the Code Making Panels, the serve the panels by acting as the recorders of the panel actions. Lastly, the screw from the clamp may be used if the clamp is removed.

Hogwash!!

Good argument!

Joe,
Both holes are threaded with the same 10-32 tap. How is one better for the purpose of connecting the EGC than the other????????/
Don

Don:

OK, I agree with your thoughts, but when was the last time you worked in an existing building trying to fish in and re-wire, or add additional circuits?

Say, the original electrician installed 4 inch square metal boxes, (1900 Boxes) and did not use all of the cable entries, removed the clamp(s) that were not used, and attached the EBJ or EGC to the screw you mention, often with no real head on it?

Now the new installer, who may be a DIY'er takes the cable into the opening where the cable is usually installed, and doesn't have a clamp like we might in our junk box?

I see that as the possible future hazard, that it could represent, because the installer will, and has installed the cable into the box without any clamps all.

I have seen this happen many times during my career, where the cables were not secured to a clamp because it was not in the box!

I am sure that some of the other "old work installers" here understand what I am talking about.

There were comments made by someone indicating that the IAEI One and Two Family includes the discussion that supports my issue and that clamps are not allowed.

It should be noted that both the present Author, and Previous Authors Simmons and Tedesco have been members of the CMP Panels involved.

Joe, I don't believe you are reaching as far as to invoke the "I used to be a panel member" argument. You know, as well as I do, that panel members have differing opinions and it is the panel as a whole that makes the decision, not one or two members.

When Phil Simmons makes a statement, I normally agree with him. The point is that I don't always agree with him, or you. That does not necessarily make either of us wrong unless the words prove us wrong.

I have asked you for the words that make me wrong and I get a response of "hogwash". I am glad you do not inspect anymore. You can only enforce what is now, not what might be in the future. You can only enforce what the Code requires, not what you think it should say.

To answer your other question, yes, I am still an inspector in areas that do not have an AHJ. I am listed in our Electric Service and Meter Manual for that reason.

Are you going to Salt Lake City? I will be meeting Ryan Jackson, Mike Holt, and a bunch of others there.

Joe,
When I do a "rope" job, which is very very rare, I always remove any unused internal clamps. I think that makes for a more "workmanlike" installation, so even if I don't use the clamp screw for the EGC termination, there is still no clamp left in the box for the next guy.
Don

Don, I've been known to use boxes with 1/2" K-Os and a romex connector(C-500). What is the next guy going to do with just a 1/2" K-O ? You can't make it idiot proof, maybe idiot resistant, but not idiot proof. This past winter we did a custom home with all steel boxes as per spec. When we went to trim out we discovered several boxes did not have the threaded ground screw hole. Just a dimple with GND stamped next to it. We drilled and tapped these boxes because the GC didn't think too much of our alternate plan of ripping the defective boxes out of the finished walls. My drilled and tapped holes weren't listed but they were made with the proper size drill bit and threaded with a tap and were identical to the other factory drilled/tapped holes in the box.

Fred: You get a green tag from this inspector.

Yes, I will be there in SLC, haven't missed one since 1981!

I am an AHJ and I would not fail someone for using the remaining screw for the grounding conductor. I would however fail you if you wrapped it around the screw the wrong way! ( It has happened more times than I can recall.) The wire has to wrap around the screw clockwise so that the wire tightens up. (Righty tighty, lefty loosey) I think that is how it is spelled!?

After reading this topic and another like it it seems that the local inspector could like using the 10-32 clamp screw or he may not. No one posted and code saying you can't so it will be up to the town your working in I guess.
I also would like to point out not one old work box in my truck has any indication of which hole the ground wire should be installed under.
My opinion is I use the extra 10-32 they give you with the box and toss the extra clamp. I like it and it works.

While we are talking about this extra 10-32, why in the heck is the screw on deep old works a hardened screw? It's not on the reg depth ones and is very tough on my cutters

Joey D,- I have no idea why the box screws are hardened, they are a pain.
Try using a 32 tooth blade in your hacksaw, works for me!

Joe, with all due respect you are taking this one way out there. Sunday I am taking a grounding and bonding course. I will bring this up as the first question. I wonder how long it will be batted around!

Why do you routinely remove unused clamps?
Don

It gives me extra space to tuck the wires and I guess that is how I was taught.
Don

I would like to ask a question on this, what type of lock nut is holding the clamp. If I had jurisdition and the contractor continued the practice, [and I see no problem in the code with this] couldn't you request a bonding bushing on the clamp? It's the only way to know you have a true bond.

I can not believe that there are so many of you guys who call yourselves Professionals, belong to IAEI, are merit shop workers, are union workers and inspect or install electrical systems that are willing to accept, install, condone or approve the mickey mouse approach of using a screw provided for use with the clamp when securing cables to the box as the means of bonding/grounding the equipment grounding conductor to a metal box. Those of you who are Inspector or associate members of IAEI, turn in your membership card. Those of you who are instructors- quit. Equipment that is designed for the purpose should be used for that purpose. I suspect those of you who approve of using a clamp screw for a ground screw have never been in a court of law and had the attorney ask pointed questions and have to come up with legitimate answers. I know it sounds like a minor thing and I now wish I would't have brought this subject up but I did and I've learn there are a lot of shoddy "professionals" out there that don't have any pride in our trade.

George to shorten your post up, your main point is you where trained a certain way and anyone that does things within code but not the same as you is unprofessional and produces shoddy work.

That is your opinion and you are entitled to it, I will continue to use any method that is code compliant.

You show me where the code will not allow any screw to be used to land a grounding conductor (other than a sheet metal screw)

Or show me any evidence that the clamp screw provides a less secure connection and I might begin to care what you think is right or wrong.

Bob

George,

Your question here is if there is any code rule against it. Opinions don't change the facts. If you're reading the responses here as recommendations I think you've missed the point.

Bill

250.8 250.8 250.8

If you guys look back at the posts I;ve put theres books I;ve shown where it says exactly what George is saying. One and Two family Dwellings 5th Edition By the I.A.E.I. page 161 ,Has anyone read it , I know thats only an opinion BUT its the Opinion of the Electrical Inspectors Association, I was Inspector for over 20 yrs. Each Inspector has to make his own call But I always used Books like thoses from the I.A.E.I. to back my rulings otherswise like you said Its then only one mans opinion

Yoopersup: I'm glad that you wrote that...thanks.

This thread and a few others have bounced around and seemingly jumbled a few different points. For what it's worth I agree that a Green Grounding screw with its wider head seems more suitable for attaching a wire to the box than a smaller-headed clamp screw.

With that aside, Re: 250.8:

I have a question... If 250.8 means to say only specific listed 'grounding Screws' must be used why does it bother to say "Sheet metal screws shall not be used to connect grounding conductors to enclosures" ??

Bill

An off the wall observation or view.

If we are using EMT as the EGC per 250.118 and use steel set screw fittings, should the manufacturer offer a green screw for this application?

OK, I'm glad I'm not on a stage right now with all of you as the audience holding tomatoes.

Roger

yoopersup, It's odd that you having been an inspector for 20 years would not stick with the code and use other books to make your rulings. How many jobs have you failed in your time for things like this and had no code ruling to back yourself up?

Thanks guys and Yupersup, I know what you are referring to in the IAEI 1 & 2 Family book. I don't have the 5th edition but I have the 4th edition and I'm sure the message hasn't changed. Another IAEI member called this to my attention and I looked it up. I've been an electrical inspector for 20 years and wore the tools prior to that. I'm a Past President of the Michigan Chapter IAEI and I strongly support as do most inspectors, the high standards the organization is known for offering.

Devil's Advocate here ...

250.8 does say that "Grounding conductors and bonding jumpers shall be connected by exothermic welding, listed pressure connectors, listed clamps, or other listed means"

If this means that a listed screw must be used then other types of installations (ie that require connection of a lug) may have no code compliant solution.

Bill

We are talking about a Direct connection of a screw to Equipment grounding conductor with box clamp screws, As far as a LUG to an equipment grounding conductor common sense says a Good connection made by a 1/4 20 ect done right well be code compliant. This started off as a simple question then guys started adding lugs ect Question Was an Equipment ground wire being hooked to a cable box clamp Screw , not a metal box , not a ground bar ect. Its not only a matter of the code to me but proper workmenship .Otherwise just grab any screw in any box hook the gr. wire to it!!I say again the Head on a box clamp screw to to small , Believe me been in the trade a long time i tried it.

Guys,
I'll take the clamp screw over the listed push on grounding clip every time. Yes, the head is a bit smaller than the green screw, but it is plenty big enough to secure #12 or #14 to the box.
Don

I don't know how much old work some of you guys have done,I myself have done every much.
When NM was first made with an equip. grd. how do you think the box was bonded?,WITH THE CLAMP SCREW!, cause there was no threaded hole for a ground screw! Hell the screw on the RX conn was also a very common method.

I remember when tapping on to knob and tube we used 12-2 without gr. also. I also remember when the equipment gr. in 12-2 was a # 14, BUT that was then and This is now. AAAAAAA the days of pulling solid tw , Things are better now so should the craftmanship.Most jounreyman back then had Never even seen a code book.Back then 314.40d was not in the code book all new boxes ul listed or labeled well have a tapped hole for the gr. screw old boxes I;m sure from stock do not.

Yoopersup,
If you are talking about landing a stranded EGC to the box, I wouldn't land that directly to a screw, even a green one. I still have no problem using the clamp screw, with the clamp removed, for landing a solid equipment grounding conductor.
don

I did an inspection today on this very thing. The electrician had used a green 10-32 for the bonding and therefore I passed it. Right next to it was the clamp, and guess what...the clamp screw was bigger!!!!

I'll post a picture tommorrow.

Ryan, I see some clamp screws that are bigger also. I checked my box of ground screws today. No UL listing on them. And no manufacturers instructions. A 10/32 is a 10/32 that simple!

I put a demonstration together.

The first two pictures show both methods.




Can anyone tell me why the 'green' screw is any better than the clamp screw?

Someone also asked Don why he takes the clamp out, well I do too and I think this picture illustrates why.



If there is going to be a short in a box with MC clamps it will be where the wires are pushing against the top of the extra clamp. Take that clamp out and there is much more room.

I had to use a wire nut on the box with the grounding pigtail as it is almost imposable to wrap the incoming ground wire around the screw due to the small space.

I consider myself a craftsman, I take pride in my job and I respect the code.

George's original post.


The answer is there is nothing in the NEC that prohibits what the contractor is doing as long as the clamp is removed from the screw.

It's that simple.

JMO, Bob

Well done Bob.

A picture is worth a thousand words as the saying goes. I do see your point for what you've done. I wonder if the box fill allowance has been violated? If you used #12 AWG we would need 13.5 cubic inches. Looks crowded even using the clamp screw hole. Check your box fill, use a green screw in the clamp screw hole, recall the inspection for tomorrow and I'll approve it:-))

George: If you let Bob use the clamp hole, what section will you site for requiring the green screw? The only places the words "green" and "screw" appear in the same paragraph of the code are for main bonding jumpers and for device terminals.

Your right I am overfull, it is 12 AWG.

I did not have two identical deep boxes handy.

Red Tag for me.

Bob

Let's call it a compromise- I didn't ask him to use the ground screw hole and he he is willing to use a green screw (I hope). Bob already told us the box was overfilled, I guess that's why he went for the clamp screw hole. He has achieved "eqivalent objectives" asked for in 90.4 Plus Bob did give us some nice graphics and I liked that.

George: What section will you cite for the green screw?

I didn't quote any section Ryan, I just used what I call a fair approach because you are right there isn't any precise wording that says "You must use a green screw for connecting the equipment grounding conductor to the outlet box" Let's use the materials made for the job. When you buy an outlet box with a ground screw in it - it's green. When you buy a box of ground screws from the supply house- their green. A person wouldn't go to the supply store and buy a box of 10/32 galvanized screws with the intent of using them for ground screws. I have yet to see a product made in the US that has a grounding terminal or a ground screw that wasn't green. GROUND SCREWS ARE GREEN. Would you use a green screw to terminate an ungrounded conductor? No. Green screws are for equipment grounding conductors.

And Ryan, don't make me resort to 90.4 or 110.2 or 110.3. I'm not kind of inspector.

George,
Why should we buy a new green screw and waste resources when the clamp screw will do the job just fine? There is no code requirement that says this screw must be green.
Don

Maybe green screws are better conductors . I will say the green screws have a bigger head on them which allows for more contact between screw and wire. But I see no problem with a properly installed wire under a cable clamp screw. I've used them before and I've also used regular fine thread screws I've dug out of the junk bin.

I use Raco metal boxes & none have a G or a GR stamped by the 10/32 ground screw hole. 1900s have a raised dimple but no G or GR.

This is ridiculous.

Electricmanscott- You are correct, So having heard all the opinions, I have decided that I'm sticking with the high standards of the IAEI and the NECA / NEIS Standards. If you do work in Michigan be prepared to comply with these standards If the rest of you in other states want a standard below that go for it. I'm out of here.

GREEN SCREW WITH A WHITE STRIPE! i had an electrician wanna be ask me "a wire to the box?what for?i'll settle for a wire with any screw(no sheet metal)threaded to any hole (designated ground,clamp hole)and sleep real good,thank you.like escott said.

I'm curious if the state of Michigan has accepted those standards?? or is it just a personal thing?

Edit:

BTW, nice dig.


[This message has been edited by walrus (edited 05-19-2004).]

George,
You can do anything you want on your jobs, but, as an inspector, you cannot enforce these standards unless they have been legally adopted by a governmental unit. To do otherwise would subject you and the AHJ to a civil lawsuit.
Don

George: Are you familiar with the following terms?

1) Malicicous prosecution
2) Assualt
3) Hardship
4) Tort


If no, I would highly suggest getting a copy of "Legal Aspects of Code Administration". It explains very well the legal implications involved with what you and I do for a living. It was well worth my 25 bucks to get it. Perhaps your building offical already owns a copy...anyway, check it out, you may find it interesting.

This topic should really be split into several threads:

1) Good practices that are not _required_ by code.

2) Legal aspects of code enforcement.

3) Is a standard machine screw acceptable as the grounding screw (this thread)

On 1) There are many good things that electricians in this forum will do, and will always do, even though code does not require it. These are things that inspectors are powerless to _require_. An example is the use of 'red heads' (anti-short bushings) on MC cable in MC cable fittings.

On 2) Remember that the NEC is _not_ law. The NEC itself is simply a list of recommendations and opinions, and in some sense has no more legal weight than Ryan's daughter It is only when the NEC is adopted by the appropriate authority that this opinion begins to count and have weight of law. If the appropriate authority adopts a _different_ code (eg the IAEI codes), or adopts amendments, then these other opinions will have weight of law. It is entirely possible that a _green grounding screw_ is legally required in some places, but not in others.

On 3) My opinion only is that any machine screw with a sufficiently large head is sufficient. A 'small form' screw with a reduced head diameter may not be appropriate, no matter what the screw thread. Devils advocate: take a look at the head profile of screws that are specifically for grounding. There is clearly a bit of a concave section that helps pull the wire into the head. Most other screws that I see do not have this head profile.

-Jon

Do I know about: 1) Malicicous prosecution 2) Assualt 3) Hardship 4) Tort? Yes, I also know about misfeasances, nonfeasances and malfeasances. Been in court many times. Always as the plaintiff. Perhaps I could have used a better choice of words when I said "adopt the Standards of NEIS" I forgot that these "Standards" are indeed legally adoptable. No Michigan has not adopted them. I sat on committee to have the '02 NEC adopted and I can tell you that we had a long hard struggle just getting the Builders to accept AFCI's. I can about imagine how they would feel about adopting the NEIS Standards. I could have said- I choose to look at the IAEI or NEIS as examples of professionalism that one could emulate. Maybe you guys wouldn't get so cranked at me :-(

George: I can't speak for everyone, but I for one am not upset with you. I think disagreeing about the code is a great way to learn it. If you don't agree with I have to say, I think you should argue it.

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"?

Remember that questions of this type have been asked many times before, sometimes even before the new kids and fledgling inspectors, and young journey-persons were even born!

When you too become a Senior in the future, and we "old guys" are gone, you'll remember how we tried to warn you, but that will come with time. Hot Dog!!

I do see where some "old guys" here are still with their personal opinions, and that's OK too!

This is fun, and "Yooperscoop: will have the last laugh I am sure!

PS: I just turned some old code books into $500.00, now I can buy a new toy!!

Joe,
Can you cite a source for that statement? I'd like to read it. Thanks.
Don

For those who do not approve of the use of the clamp screw for EGC connections, I have 2 questions. Do you accept the use of the listed push-on green clamp for the termination of ECGs at a box? If yes, can you honestly say that you believe that the push-on clamp is a better grounding connection than the clamp screw?
Don

Joe, maybe, but obviously they weren't answered, or if they were, the answer wasn't very substantial.

True case, my cousin had a degenerative eye condition and actually lost the vision in one eye before the cause was found and treated. If the cause had not been diagnosed he would have lost the other one.

My Aunt and Uncle had traveled great distances and spent allot of money taking him to specialists and eye clinics.

In the end a young Doctor (a pup) just out of college recognized the disease.

All the oldsters were ignoring a simple cause because they were to set in their ways.

Believe me, I'm set in my ways too so I fit this stereotype, but I know not to ignore or diss (did I use that word correctly ) the young and upcoming.


Roger



[This message has been edited by Roger (edited 05-20-2004).]

I am truly baffled, still this goes on and no one has shown a reference from the NEC that requires a green or listed screw or even more off the wall, a listed hole.

If you can not show a reference to the NEC or at least UL you can not say it is a violation.

(Roger you so Phat, I think I used that right )

http://www.ighetto.com/html/jive.shtml

Box (Grounding Provisions (314.40d
Equipment Bonding jumpers (250.102b)
Connection of Grounding and Bonding Equipment. (250.8)

Forgot to add (250.148a) Metal boxes

Yeah,"means of a grounding screw that shall be used for no other purpose or a listed grounding device".
Lets knock this around!

Yoopersup, which of those articles and sections mention a green screw.

As Bill brought up earlier, if the screw must be listed we have a much bigger problem.

Roger

Another observation here. See what happens when the word "Opinion" comes into play.

Hold everything here. After reading Joe's last post this has evolved from the screw to which screw hole you can and can't use. That is even more ridiculous than which screw to use. Either way nobody has shown any type of refrence that disallows anything.

Round it goes, where it stops, nobody knows.

I agree with those that cite the need for a code rule and UL documentation. If it is not written, how can a rule be enforced?

BTW, I checked my "box bin" and none of them have "GR" stamped in them, and they are from Steel City, Raco and Thepitt.

Read the Articles I put up PLEASE.
250.8
CONNECTION OF GROUNDING AND BONDING EQUIPMENT
Grounding conductors and bonding jumpers shall be connected by (now this is it guys )
exothermic welding (well we:re not going to cadweld to the box) listed pressure connectors(the ones we all hate and think are useless) Now this is it !!!!! L I S T ED Clamps(get that LISTED) or other (here it is again ( L I S T E D) clamps or other L I S T E D means. Notice LISTED listed listed, Are your clamp screws listed ummmmmmmm I THINK NOT! now theres the code section how can you read it any other way. ( by the way I have never said Green screw look back at all my posts) By the way I called ul talked to head electical guy there , He well be bringing this up in a Future issue of electrical contract Maz. Geee I wonder what it well say ??/

Yoopersup,
First what is the UL listing category for a green screw? I can't find it in the white book. Second, if you insist that this screw must be a listed grounding screw, then we will have no way of attaching larger conductors in other enclosures or to bus bars.
Don

Man your sure stuck on that Green screw ! Like I said DID NOT SAY GREEN did I. As far as to the bar ect Again what are we talking about. A bonding jumper in a Small(not 24x24 not 18 x 18 But a device box , why do you keep going off on gr bars large boxes ect. PLEASE stick to the subject at hand. Never said green Please go back look at all my posts. I am also not saying using the clamp screw hole for a proper gr screw would not be allowed,

Yoopersup,
Ok, you didn't say green, but you said listed grounding screw. What screws are listed for the connection of EGCs???? Show me the listing category. I keep bringing up larger conductors because you can't have it both ways. If the 10-32 screw used to connect the wire to a small box has to be a listed grounding screw, then the same rule would have to require the use of listed grounding screws or bolts for all grounding connections. These items do not exist.
Don

[This message has been edited by resqcapt19 (edited 05-20-2004).]

To me it all comes back to this. a regular nut and bolt are ok but in a device box it has to be green and/or listed. I think I'm going in to Wesco today and buy a box of 10-32 green screws and see if they are listed

That is my point, we can't have it both ways. Either all screws and bolts used to connect grounding conductors must be listed, or none of them must be listed.
Don

Guys,
It appears that I'm wrong on this issue. CMP5 addressed this in the '99ROC. It is still not completely clear as I don't think that the "green" screws are listed devices for grounding and if they are not, then the only choice would be the push-on grounding clip.
Don

.

Wouldn't this mean green screws??

Why don't they just come out and say "Green screws"?

Russell

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

JFYI, I used an Appleton 4" sq. box on Fri. that had "GR" by the tapped hole, and also 3 1/2" deep sw boxes.

Mannnnnn..... The neverending thread... kinda like the ground pin up/down issue. Just put the screw in,and paint it green

[This message has been edited by txsparky (edited 05-23-2004).]

UL does not list individual screws for any purpose. UL does list assemblies.

So, based on the code panel negative comments, the only choices for a UL Listed "conductor directly to box" grounding connection would be either a push-on ground clip or a factory built "pig tail and screw" adapter installed in a factory threaded hole.

But instead, of connecting the conductor directly, choose a mechanical lug or a crimp lug/terminal (i.e. Stakons). These can then be installed using any method (including any hole) approved by the manufacturer of the connector.

Originally posted by CharlieE:
Thanks for the beers Charlie. I had a wonderful time.

Bob,Don, Ryan,
It looks like you guys were correct regarding the use of the clamp screw or any other screw besides than a sheet metal screw as prohibited in 250.8. Art. 250.8 speaks to the general requirements of grounding and bonding conductors, which are required, unless modified by another article. So, unless another article modifies the requirements for the connection method "shall be connected by exothermic welding, ..., or other listed means." , then that is what is prescribed by the code.

However, when one reads 250.148, which was mentioned above but not considered at the length 250.8 was, one finds "(A) 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 or a listed grounding device."

Unless I have missed another article, or something, this is the specific modification of 250.8 that pertains to metal boxes used for specific purposes. (IMHO, 250.8 and 250.148 are two ends of the same sausage, just separated by a lot of intervening stuff.) Specifically, absent an NEC definition of the term "grounding screw", one uses normal English rules to determine the meaning. I.e., the screw is the noun, and grounding is the adjective that describes the function of the screw. No where in Art. 100 are "screw" or "grounding - adj." defined specific to the NEC. I do not see in 250.148 the use of the term "Listed" or "Green" describing the screw, only the prescriptive restriction that it shall be use for no other purpose. Furthermore, "a listed grounding device" (ground clip) can also be used. The article does not prohibit drilling and using any old hole for the connection, within the restrictions on boxes and enclosures elswhere on substantially reducing the strength, or positioning of fasteners, and with the restriction that conductive paths other than AWG size conductors shall be properly sized. (That is, you can't use a 2-56 screw for a 15 amp circuit lug.)

I don't have the references as we don't own them, but "been there, done that, got the T-shirt" on this one with a supplier.
Jim

Just came across an excellent article pertaining to this subject in the March, 03 Electrical Contractor Magazine, page 134.

I dont have anything to add to this discussion so I wont.