Is it clear that a bonding jumper is required between the green screw of a receptacle and a metal box when the receptacle is mounted on a 4 inch square raised cover?

No, not clear at all.

In the latest edition, you still do not require such a bonding jumper if the cover has the 'dimpled' corners, or, IMO, for a metal cut-in box.

The 2008 NEC is where the distinction was made between the covers with the dimpled corners, and the nice, square-face covers. I'll see if I can find pics.

OK, herre are the pics!

This one still does not require a bonding jumper:


While this style cover does require a bonding jumper:

The receptacle also need to be permanently attached to the cover by rivets or screws with a thread locking means.

I would want to see the listing of that cover/receptacle combo ... or a bonding jumper.

If I really believed nobody would ever loosen the screws on that cover with the power on I might be a little more easy going

2008 NEC Code handbook Page 254 ( 250.146 ).
Handbook has photos & Explaination.
Yoopersup

Thanks Ernie- Looks like most installations will need a bonding jumper if the receptacle is field installed on a four square raised cover. Just followed your tip and looked in the '08 handbook.

You going to be in Ann Arbor 12/3-4/09?

Where 250.146,[A] references "a rivet or thread locking or screw locking means", would this include those little 6/32 nuts with the machined serrations or the serrated lock washers attached to them?

I've always just connected a pigtail to the device, but would be good to know the details.
Other than looking up the individual manufactures listing, is there any identifiable marking on these covers that would indicate they are listed for grounding?

KJay, as I understand it, the supplied hardware does meet the code requirements for the 'screw locking means.'

Murphys' law being what it is, I next expect the folks who brought this on - remember all those rants against metal boxes on the ends of extension cords, with pictures of the assemblies missing screws and coming apart? - to start ranting anew when they find some place where "Loctite" was applied to the hardware.

Make no mistake about it; there are those who will find fault with everything. These are the folks who won't be happy until EVERY device has a pigtail and EVERY circuit has a gree wire.

No, there is no speciific marking on the packaging regarding the use of pigtails.

Which, of course, brings up another 'detail.' Virtually every cover of this type is made by one of two firms. The code change only impacts the one company's product; 'corners in' or 'corners out' was simply a style difference between the two firms.

Unless they get the assembly listed as being suitable for grounding the corner style is academic. I am betting, when they do it will be stamped in the cover. I certainly expect to see a full page, glossy, ad in the IAEI magazine.

Yes I am one of those people who thinks every circuit should have a green (or bare) wire ground.
Fortunately, for me, that was the way all state RFPs were written so I didn't have to split hairs about it.
I am just a spectator now so it really doesn't matter too much what I think.

Presenting the opposing point of view:

1) I see no rewuirement for the cover to be specifically listed as a grounding means; just that there be some method used to prevent the screws from vibrating loose; and,

2) I have, nor has the NEC had, any problem with metal conduit being used as the ground conductor. If anything, this pronciple is reinforced with the new "MC smart,' that does away with the need to have a green wire in MC.

250.118 Says EMT & Rigid Ect are approved equipment grounding conductors, But we"re not talking about raceways here. As I stated before 250.146 Clearly States & shows (Pics & All in handbook page 254.)The direct metal contact referes to a Surface box & the outlet put directly to the box (example handy box) , Not via removeable cover. A Pig tail for that type of cover (removeable is required. I Know the handbook is not code But I;ll bet you a lotta Inspectors ect go a lot by it .George bring it up at the Dec. Meeting.
Yoopersup
Yoopersup

Oddly enough, 250.146(A) directly addresses this point, specifically saying you do NOT need the jumper for the covers with the "flat, non raised" corners. At least, that's what the text of the code says.

In the handbook, the illustration right next to the section (pg 254) says the exact opposite. It appears to me that there's a typo, the word 'not' having been omitted from the artwork.

Keep in mind that this same section would apply to 'cut in' or 'old work' boxes, which are 'surface mounted,' even though the bulk of the box is within the wall. That is, 'old work' boxes do not require the use of jumpers.

Likewise, bonding works in both directions. That is, if the box does not require a jumper, then there is no need for one - even if the ground wire is terminated directly to the device. That's how I see it.

You are still left with this

As for the new MC, time will tell.
I give it about a 50:50 chance that there will be a problem with a failed ground and there will be a big stink about it.
It will just depend on whether someone gets hurt and the family sues.

"Listing" is something that is simply unknowable from looking at a picture, or some artwork. One would have to see the packaging.

That also brings up the bugaboo regarding the 'combination.' What if you have a Raco box and a T&B cover? Though both are built to the same NEMA spec -unlike circuit breakers, which can be any shape or size- you're opening the door to another similar dispute.

I'd love to see UL weigh in on this. Do they have a separate listing standard for these covers? Do they consider mixing manufacturers an issue?

All of these efforts at nit-picking do nothing to detract from the pictures I posted, to illustrate both the 'flat, non raised' cover from the other version. I'd say we have to give that version the benefit of the doubt.

Which, of course, leads us to respond to the OP: "No, the code has not essentially required that all cover mounted receptacles have pigtails." Had the code panel wanted to say that, they would have done so.

The later assertion that 'this section was meant to apply to handy boxes' is also shown to be in error.

250.146A states Direct contact between the BOX & the Yoke or Device.250.146 B then states Contact devices or YOKES designed and Listed as self grounding ect ect.
Thoses sections are refering to Yoke & Device connections Not Box cover connections.
The 2002,2005,2008 Code handbooks all have the same info and pics! Guess there all wrong then???
Yoopersup

If you have a cover with a riveted receptacle you are good to go.

Beyond that we are asking "what is a thread locking means".

I can't speak for the other editions, Youpersup, but your presentation of what is in the 2008 handbook is in error - as is the artwork in the illustration. Earlier editions did not reference the 'flat, non-raised' parts of covers, as that is new to the 2008 code.

I say the handbook is in error, becuse the language accompanying the artwork is exactly opposite of the code section - which is printed right next to the artwork. They both can't be right.

As for thread locking, there's really nothing vague about that. I mean, "Machinery's handbook" and other shop references are replete with discussion of the various means. Since no specific method is called for by the code, I'd have to accept any method. Naturally, some of these methods cannot be identified without taking the thing apart - and such action might destroy the thread-locking mechanism.

All these semantics being tossed about, attempting to extend the code beyond what it says, remind me of the 'sheet metal screw' silliness of a few years back. I submit that if we're reduced to arguing what the meaning of 'is' is, then perhaps we have bad code, that the code has crossed over into design work - something the code explicitly states is outside its' scope.

Now, if someone has a different understanding as to what the code is referring to when it speaks of 'flat non-raised' parts of covers, I'd love to see a picture. As best I can tell, the code was written as it was so as to specifically allow the use of these covers without need for a jumper.

So, is it safe to say that none of these covers are currently listed for grounding?
Is this perhaps another one of those NEC catch 22’s, something like the AFCI outlet devices that don’t currently exist, but we can supposedly use?
BTW: I see that Siemens is finally releasing a 2-pole combo AFCI CB.

I would believe any cover that had the receptacle riveted to it as an assembly was OK, even a field riveted assembly. I would also go for a nut that had the locking mechanism, either the domed nut with the plastic sleeve in the end or one with a pressed dimple on the side. What I would be skeptical of would be a regular machine nut or one of those stamped, threaded things that comes sometimes with a cover. They are trying to be sure this receptacle is not going to come loose from years of plugging and unplugging. That was why they did away with allowing the single center screw to attach them in the first place.

I haven't looked but I would be surprised if someone is not selling a cover/receptacle assembly that is riveted.

Code States as Follows. 250.146(A).
This provision Shall not apply to Cover-Mounted recepacles UNLESS the BOX & COVER (Combination) are LISTED as providing satisfactory ground continuity between the box and the Receptacle.
Just produce a LISTED box & Cover (Combination) to meet that requirement & subject well be closed!
Otherwise Gotta put Pigtail as I see it.
Yoopersup

Kjay, all that's safe to say about the listing details is "I don't know." That's why I'd love to have UL weigh in on this. I am not familiar with the specific testing protocols, but those folks are no fools, and it's very possible that their suitability for grounding has always been a part of the standard evaluation.

UL white book or there number is 1-800-595-9844 .

Very nice .... how about posting your citation here for all to see?

Asking to see the listing is the same thing you would do with any piece of equipment that is required to be listed.
I really do expect that as soon as this question gets asked enough times one of the manufacturers will stamp "suitable for grounding" on their cover/receptacle assembly and charge a buck extra for it.

Sorry, Greg ... in this discussion I cannot accept someone implying that "UL says" and leaving us with their phone number.

If it's in the white book, for Pete's sake either quote from it, or copy and paste it.

If someone at UL said so, I want that correspondence also posted - and the name of the person.

The other alternative to to shut down the forum, as it's obviously not a way to learn anything.

I never said "call U/L". It is reasonable to ask for some kind of listing tho, when the NEC specifically says



It is up to the installer to demonstrate that, particularly when we are just talking about 8" of wire and a screw.

Gentlemen & Ladies (if it applies) Since I was the one who started this war, I guess I should make a comment from time to time so you know I'm monitoring. I just looked at the 2008 Analysis of Changes published jointly by IAEI and NFPA and maybe we can get a uniformed understanding after reading what it says on p. 132. For those of you who don't have a copy, I think they realized that there is this problem and they are trying to fix it by adding a new last sentence to 250.146(A). They are saying that if the receptacle is riveted or installed with some sort of thread locking or screw locking method it does not need a jumper installed between the green screw on the receptacle and the metal box. Nothing about the cover and receptacle being a Listed combination.

Works for me.

Theres Two parts to 250.146A
One is :This provision Shall not apply to Cover-Mounted Receptacles UNLESS the Box & Cover combination are Listed as providing Satisfactory Ground continuity between the Box & Receptacles.THE 2008 Analysis book doesn't deal with this as its not a change.
Part two is:A LISTED exposed work cover shall be permitted to be the grounding & bonding means when attached per # 1 & 2 as stated.
I'm saying either way a LISTED cover is required or a Pigtail is then required.
I never said UL says I just gave the number & White book as a reference which all of you should have to reference answers you"ve been giving.
Yoopersup

For me anyway, the "thread locking or screw locking means" mentioned in 250.146[A] is where the question arises.
Some form of written confirmation from the manufacture that the device fastening hardware included with the raised covers is satisfactory for the purpose would probably clear things up.
Seems like it should be okay since the covers themselves are UL listed.

I just did some very unrewarding looking in the white book. The NEC to U/L cross reference for 250.146(A) sends you to QCIT on page 257.
With titillating glee I flipped to that page expecting a definitive answer to this conundrum but, alas, it don't say squat about grounding devices in the cover.
I then followed the reference to ANSI/UL 514D in google and got less than squat. The scope of this standard and the dozen standards referenced by this standard don't seem to address this grounding issue either.

At this point, if I was inspecting I would scrounge around on the floor, find some wire and put the jumper on myself. It wouldn't be worth arguing about it anymore

Realistically I am not sure how I would know it wasn't there anyway unless I opened the box. I suppose this happens when the question comes up in the office and somebody takes the time to look.

We are really left, at this point at what is an acceptable thread locking device. Is that just a lock nut? (you need 2)
If John had a box of these



we wouldn't have spent 2 days on this.

Yooper- I'm going to meet you half way. I don't think the wording is there if they want the combination receptacle/cover unit to be Listed as an assembly. I think they definitely want the cover to be Listed and have a non-raised flat surface where it fastens to the box but I would accept a receptacle being installed in the field using the technique described as a rivet or locking thread type install. I think if it had to be built in the factory and Listed as an assembly they would have said it more emphatically.

As Greg said- They just don't want the receptacle to come loose.
Hey- they let self-grounding receptacles slide in 250.146(B) and I think that's really shaky.

BTW did anyone else notice that in the "domed cover" picture up thread a ways that they didn't have any screws in the yokes of the receptacles, just the center screw?

Oh and they didn't use primer on the plumbing pipe below.

Those guys all need a "tune up".

George
Look on page (224) 2008 analysis book & page 495 NEC handbook . Switches using raised covers. There they don't mention anything about Listing or type of covers required.
Yoopersup
Either a Outlet or a Switch is a Shock Hazard if cover is loose or pulled away from the box without a grounding tail.
But like the man says maybe time to move on. Always interesting to get others views on theses problems.

I tend to go on by discussions that go on for several pages since I can't sit still long enough to read all the posts. At the same time, I am a stickler for proper grounding and bonding mainly because it is so misunderstood and its the end user's last line of protection during a electrical fault. Here’s my two cents to get some peoples fruit of the looms up in a bunch and I apologize before hand if I repeat anything already said.

To answer the OP, it is clear enough to me. To validate a listing, you do not go to the category description. You go to the manufacturer’s separate listing to validate it. In other words, if I saw a recept missing the jumper and the electrician quoted 250.146, (s)he better cough up the product’s listing stating that.

It even states in 250.146(A) that this provision shall not apply to cover mounted receptacles unless the box and cover combination (made as a set) are listed for proper grounding continuity. I am not sure I have ever saw one before. This tells that someone, somewhere make a box, cover combo that is listed as such. Rule of thumb, must have jumper or product documentation stating otherwise.

As for the raised covers, like Reno pics in his post, the NEC handbooks states the 250.146(A) does not apply to these types of covers. Go now and chastise me gently. I do not want my feelings hurt if I had any.

Sorry if I posted pics that were less than perfect, and showed other issues as well . Send me another pic, and I'll put that in; I guarantee that I wasn't thinking of this issue when I took the pics, and both are cropped from much larger pictures.

(It is worth noting that the 'two screw' requirement - which says nothing about using two nuts as well - is also a fairly recent addition to the code. That's another discussion).

Another variation of this issue involved the "nuts" used by one manufacturer. Rather than being any type of standard hardware, they are little clips that you slip over the yoke. These gizmos further drive home the point that you can't inspect for this without taking things apart. It's one thing to call for inspection before you fill a ditch; but to call before closing every box is absurd.

There's not a product in existance that doesn't present additional hazards once you start taking it apart. Removing the cover is not something that happens in the normal use of a receptacle. Moreover. its not true if the ground wire terminates at the device, with no direct attachment to the box. As I said before, bonding works in both directions.

Sparkyinak again stresses the problem with the 'listing language.' I'm not sure there are any devices, covers, or boxes specifically listed for use with each other. Rather, all are made to NEMA specs that define dimensions, etc., and that has been good enough until now. If the code panel wanted to say 'must be manufactured and listed as an assembly,' they need to say so.

I disagree that the handbook states that the code is not discussing these covers. The language of 250.146(A) seems specifically written for these covers, and the handbook illustrations show these types of covers. I can't imagine what else the panel had in mind, unless it was complete, manufacturered assemblies - in which case they need to say so.

These covers are very common; if the panel forgot they existed, then maybe they need to get out of the office more often.

Let's remember how this whole thing got started.

At one time - mayne for the 96 edition - there was a fear expressed thet using the mounting screws alone as a means to bond an outlet to the box was not a very good idea. Now, this discussion had been going on since at least the 60's, with all manner of discussions about fiber washers vs. metal clips, etc. Since the code allows an 1/8" gap between the mud ring and the face of the wall, though, the discussion focused on using the #6 mounting screws as the only bonding attachment. At that time, the jumper requirement was added for receptacles, but not switches.

With that change, the jumper was not required if there was solid yoke to box contact. To make that more certain, the next change required the box to be mounted on the surface; that way, there was no doubt that there was solid yoke to box contact.

Then the fear was expressed that, with these 'industrial' covers, we were relying on just the one screw, the one holding the receptacle to the faceplate, to make our bond, and this screw might come loose. That's when we got the requirement for there to be two screws.

Now it appears someone felt that there just wasn't enough contact between some covers and the box, so this 'flat, non-raised' mumdo-jumbo gets added.

In a few short years, we have gone from the jumper being the exception to a view that you need a jumper, no matter what - and it's all been done one step at a time.

Agreed

if the NEC uses an example, it should be done in a manner of this is the way it should be, not "this is the example we are not talking about."

Although my job requires me to stay In the books. I am better able to interpret what is written, I can see how the passage in 250.146(A) can throw someone. I have found that to better interpret something is to read it out load slowly. If it sounds hinky, chances are, it is. At least my eyes does not always catches that. The just go, "there is something here that seems out of place."

so if you see me on the street talking to myself, I am just analyzing. Really

This whole thing gets fixed in 18 months



That is one thing about the current way the code works. If you don't like something, wait a minute.

But that still may bring up questions about listing and/or labeling.

_______________________________________________________________

Agreed.

Even if they have the nuts, it ain't listed, I would not approve it as an inspector. How ofter do we open those boxes while that ae hot? are they still grounded? Duh, no. How many raised boxes have we come across where the cover is loose or cocked? Is it still effectively bonded without the jumper? I use jumpers even on boxes where the yokes are in direct contact. After years of use the screws loosen up, without that jumper. Just because its code does not mean it is addiquate. If is my call, its getting a jumper.