ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

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.

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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.