I have a situation where a EGC will not fit on the neutral bar in the service equipment. I have tried to find a listed and same manufacturer add-on grounding lug kit to no avail.Except for the article 110 listing requirement issue is there anything wrong with installing a bolt-on lug of proper size and bolting it to the side of the panel with a nut and bolt? Code references please. Thanks

Greg:
I don't have the bible handy, but...
Common practice around these parts has been:

Drill enclosure, as required.
Remove paint from enclosure.
Mount suilable size lug.
Bolt, nut, flat and STAR washers.
(Internal/external lockwashers)

John

Yep, and just remember EGC- ok, GEC-not ok, must be bonded to the grounded conductor at the service.

What size ECG is this? Many panels over the last ten years or so will accept #14 -#4 in every hole. The hole might look too small, but break out the inspection mirror and look real close, or look at the label for the ratings. You might be surpized to find it might fit. If not you can bolt just about any add-on lug, or bar, in the method John described for EGC.

I would drill and tap a hole in the panel and mount a lug. As long as the neutral is bonded to the enclosure properly it should be sufficient. Don't listen to sanding the paint off the panel. This is not required and in fact in itself a violation of the code.

Paul,
When is the last time you read 250.12????
Don

Don

When was the last time you read 300.6 Protection from Corrosion, or the other articles that require that paint protecting the enclosure. Possibly you require the removal of the Neutral bus and the paint sanded off although the UL listing and the code approves bonding through a screw and a tapped hole as long as it is not a sheet metal screw.

Paul

Paul, if your fitting or attachment is designed to penetrate the coating or paint that is required by 300.6, then you are correct, if not, 250.12 trumps 300.6.

If you don't agree with this, then the two article sections are in contradiction of each other, and I would choose to violate 300.6 and go with 250.12.

Remember a threaded hole is not required for this attachment, it is simply a preference, a bolt and nut can be used.

Roger

In my opinion all of you are flirting with disaster.

Most panels are not made of cans with thick enough metal to take the required two full threads when tapped.

Removing the paint to attach a lug is dangerous for the stated reason, and, the unreliablity of field installed lugs. (What nationally recognized testing labroratory has tested these connections and has detailed the steps to follow?)

The only grounding connections I would approve are the neutral or ground bus, the supplemental grounding bus kit (installed in the pre-formed holes, using the included self-tapping screws) or a grounding bushing.

IMO after removing the paint for the required non resistive connection, you should hit the bare ferrous surface with this, or something like it after making your connection.



A rusty connection is just as resistive as a painted surface.

Paul,
The hole(s) provided by the panel manufacturer for the connection of the main bonding jumper or the connection of the equipment bonding bus are not the same as a field tapped hole. The hole is punched first, providing a greater thickness to be tapped and better contact. That being said, I don't see how that is not a corrosion problem if removing the paint under a lug is a corrosion problem. Also if the interior of the panel is subject to corrosion, I think that there are much bigger problems than the corrosion of the can.
I don't see this any different than field cut threads on conduit where the factory applied corrosion protection has been removed by the act of threading the conduit. The code provides a provision for this and the same method could be used in the panel if there is a potential corrosion problem.
One more point on this, the orginal question is talking about a "large" conductor that won't fit on the provided neutral bar. To me that would require a screw larger than 10-32 and if the screw is larger the screw pitch is larger and the tapped threads in the can will provide very little contact.
Don

early, what do you mean by this?


You do not get to pick and choose the method of bonding connection, as long as it is not a sheet metal screw it is acceptable to the NEC.




[This message has been edited by iwire (edited 11-19-2005).]

As a legally authorized AHJ, I do get to approve the connection (90.4 & 90.7 & the definition of AHJ in 100).
If I feel that a grounding or bonding connection choice is not sufficient to provide a low impedance to ground, then I can, and do, refuse to allow it (250.4(a)(3)(4) & (5) and the definition of bonded in 100).
I can and do sometimes reverse my decisions upon the submission of additional information or test results. My decisions can also be appealed to a higher authority (90.6 and local regulations).
I do not hold a grudge, the aim is a safer installation (90.1(A)), and I choose to err on the side of caution.

gserve

"I have a situation where a EGC will not fit on the neutral bar in the service equipment. I have tried to find a listed and same manufacturer add-on grounding lug kit to no avail.Except for the article 110 listing requirement issue is there anything wrong with installing a bolt-on lug of proper size and bolting it to the side of the panel with a nut and bolt? Code references please."

You did not mention specifics: manufacturer, wire size, panel...

I find it hard to believe that such a grounding lug is not made. Typically you have to look around in the catalog to find it. Give us more information and our crowd might know what you need off hand.

I know that all of the major brands have kits that cover the whole range of possibilities.

early are you really an AHJ or are you an inspector?

In my area they are not the same thing.

We will have to agree to disagree as I do not believe either 90.4 or 90.7 allows you to refuse NEC allowed methods.

Corosion Resistive coating is required by code. Code does not require it at tapped holes for grounding unless I am missing something. I think not because you did not reference a code article on the matter. Only an opinion. Might I suggest you contack someone like Sq D or Hoffman who manufacture enclosures and ask them what UL approves as far as grounding an bonding. As as you will note 300.6 addressesCorrosion Protection both inside and out. Another good reference is Soars.

Resqcapt19

Actually the hole in the back of the panel is rounded in order to allow the panel to sit flat on the wall after the screw in inserted. There is really no more steel provided at that point.

e57

I agree rusty surface is as bad as a enamel painted surface. The problem with what you are showing with the can is that the code does not require it as it does when threading righd conduit. If it was required the code would say to use it. If the code does not say it then the inspector has to accept the fact that means and methods are the contractors. After all it is his moiney you are spending.

Paul what exactly is an "NEC Specialist"?



Yes sometimes it is rounded for the reason you stated. Usually that is not the reason as the panels mounting spots will be raised so that there will be air space behind it.

If you take the time to look carefully you will see the displaced metal from the hole punching process makes the spot where the threads are a bit thicker.

Bob



[This message has been edited by iwire (edited 11-20-2005).]

iwire,

I come from almost the same place you do. One state under. OK, technically, only the BO can make the call, but if the BO delegates that responsibility to an assistant, then that assistant then has AHJ power. I am a licensed BO, electrical contractor and electrical inspector in my state.

I do not refuse NEC allowed methods, but I do not approve methods that I believe are inferior either. What section of the NEC allows your method? I have cited several that require a low impedance grounding connection. Where is your method cited as an approved connection method?

By the way, we cannot chose to violate any sections of the code, in order to "trump" another. All sections of the code must be met.

Going back to the origional post, the guy wanted code references to allow his bolted on lug. There are none I am aware of. I do believe his search for a listed ground bar kit was ended prematurely.

gserve, what manufacturer makes your panel? How about a universal ground bar kit? Are any of those UL listed?

I think that is pretty clear that paint needs to be removed.... Outdoor grey painted panels will have paint also in any hole for grounding or bonding meathod. Short of re-painting the surface, after contact is made,(which I think is a bad idea... see 110.12(C)) something like NOAL-OX, Zinc paste or the stuff I posted a picture of to protect against corrosion on the electrical connection is required, depending on environment. IMO If in an indoor panel, I think its a non-issue... Outdoor panel in salt air, different story.


Either way, I think a treaded connection in a thin can for a large lug w/ a large conductor like a bonding jumper is not mechanically strong enough for the purpose. And personally tend not to even trust the connection provided with panels connected by a 10/32. I don't know my own strength and tend to over-torque them...

Earl, the more correct question would be "what section prohibits it?" the NEC is a permissive code.

That is what you should do, so how do you ignore 250.12?



Now, if the fitting is designed to penetrate the paint then the finish is compromised anyways isn't it, so what happens to 300.6 now?


You can not eliminate one requirement for another.

If the enclosure is soley protected by enamel, you would be with in your rights to have the installer paint over this area after the lug, bar, or what have you is installed.

90.4 obligates you to enforce all the code, it doesn't allow you to ignore sections of it or add to it.


Roger



[This message has been edited by Roger (edited 11-20-2005).]

I am not ignoring or adding to the code. In my opinion, the attachment of a lug to the thin metal of an enclosure like a panel box cannot be made securly enough to provide a low impedance grounding path. In my small area of jurisdiction, my opinion counts to the degree as already discussed. In another inspector's opinion this grounding method may be OK, I don't know. I could have my opinion changed by evidence to the contrary, but I don't see such evidence presented here, only opinions.

I will say this: I have approved using grounding clamps to building steel (a much thicker metal) by using the method you have described. Threaded holes (with at least two complete threads) or bored holes using corrosion resistant bolts with locknuts are OK with me, so long as the paint is removed, and the metal is protected from corrosion afterwards.

earlydean,
So I assume that you do not permit the use of listed equipment grounding bars. Their only connection to the panel is the threads of the two 10-32 screws. A lug bolted on to a clean (bare metal) would have less impedance than the listed ground bar.
Don

Don,

Of course I would accept a listed ground bar installed in accordance with that listing. I have stated I would already. Listed assemblies have been tested for their effectiveness.
110.3 contains the rules I must follow.
Please note as well 110.2 which gives the AHJ the authority to judge what is acceptable or is not.

My point is that a lug bolted to the bare surface of the panel would be a far superior connection than that provided by the two 10-32 screws that provide the current path for the listed equipment grounding bus.
Don

110.2 is aimed at the AHJ, I do not know who the AHJ is in CT but I will be surprised if each local inspector is in fact the AHJ.

I imagine like MA that would be the State.

By the way along with MA and RI I am also licensed in CT. I had to take a separate code update for my CT license, what a pain.

Bob

E57 agan are yu saying a tapped hole is not a good electrical connection and what code reference do you make not allowing a tapped hole as long as not a sheet metal screw. Why do you insist on violating 300.6.

Early:

Again you are ignoring the manufactures instructions and UL listing. The manufacture provides you with tapped holes for both the ground bar and bonding the neutral. The instructions do not instruct you to sand the panel. In fact in a discussion I had with a Hoffman Engineer he explained to me that they had a grounding kit and that if sanding of the paint were done then the warranty would be null and void.

Rescapt:

Not necessarily. I just had a transformer that was installed 2 years ago and we relocated it. I noticed where the inspector at the time had required gouging the crap out of my electrical equipment had been done that rust had built up. Surely, you would admit that when the electrical panel rusts out around a bonding connection you have defeated the simple defination of bonding. Perminent. It does not say perminent until it rusts out.

Paul,

I didn't say to violate the manufacturer's warranty. You must be thinking of another respondent.

Bob,

I hear this misconception all the time. There is not a single AHJ who has supreme power over every thing you do. There are many AHJs who each have some authority over what we do for a living.

In CT, each local town will have the local AHJ (building official), and the State has the State Building Inspector, who the local AHJ may have to answer to.

The NEC references the AHJ as the person, organization or office that has authority over the electrical installation, such power often being granted by legislative act. (Article 100, check out the FPN)

Every job has multiple AHJs. (Even in Mass.) We all answer to the fire marshal, the electrical inspector, the building official, the licensing inspector, the insurance company and the tax collector. All of these are authorities having jurisdiction over some aspect of our work, often overlapping.

Paul,
And that would not have happened to the threads for the 10-32 screws that bond the listed equipment grounding bus to the panel?
Don

Paul,
Given that transformer cases do not have manufacturer provided tapped holes to make the required bonding connection to the case, how do you make this connection?
Don

[This message has been edited by resqcapt19 (edited 11-20-2005).]

I just read this thread for the first time. If I was a novice, my mind would have been going back and forth (like watching a tennis match), as both sides offer good arguments - but the bottom line is I would be confused as much as amused.

With that being said, I will add my 2 cents , Please let me add to the confusion/amusement.

Yes when the factory punches the enclosure, the dimple has more metal, and the factory threads will have more threads for connection.(tested and listed with the enclosure)

Adding a lug to the enclosure is permitted, as long as following the installation instructions, as the NEC is a permissive document, and I do not see where it directs one not to add a lug. That being said, the paint as per 250.12 is required to be removed to provide for lower contact resistance. Threading a field punched hole in the enclosure will not provide enough threads, so a nut and bolt connection should be provided - of course with the proper torquing .

"300.6(A)... and support hardware shall be suitably protected against corrosion inside and outside (except threads at joints) by a coating of APPROVED corrosion-resistant material." ... That does not say paint.

In this requirement, I do not see where it mentions that the protection has to be factory provided. Just that protection is necessary - approval is by the AHJ.


Add a lug, scrape the paint - exposing the metal surface, nut and bolt, and if the location is such that protection from deterioration is necessary, add an APPROVED material to protect the exposed enclosure.

Remember - JMHO

Don:

I would make that connection by drilling and taping 1/2-20 providing a lug and 2- 1/4 20 hex nuts to actually lock the connection tight to the threads and enclosure.

On the project we use a GE Mini Load Center with a 480/120/208 transformer with a 12 circuit panel all in one enclosure. That is exactly the way GE provides a ground attachment. That is less one hex nut. They only use one.

Resqcapt:

I would say no since the tapped hole is installed by the manufacture and supposedly the panel has been tested by UL. Plus the fact that I don't recall ever seeing one rusted at the taps.

Paul,
So the only metal to metal connection is the threads? There is no way that 1/4-20 threads have enough metal to metal contact in a field tapped hole to provide an adequate electrical connection. What is the gauge of the metal? The commonly used 10-32 screw only has ~2 threads engaged in field tapped holes in many types of electrical enclosures. The 1/4-20 would have less. If you don't clean the paint off of the enclosure this is the only current path. I don't see it as suitable.
Don

This thread has been interesting with all the commentary on field mods for attaching a conductor to the enclosure...BUT, I am still back at the beginning wondering how comes an EGC larger than the panel will accomodate??? What is the panel mfg/model and the circuit specifics?? Just curious.

Resqcapt:

I notice that you continue to tell me I am wrong but you still do not accurately quote the code. Whats up with that?

Paul

I have been reading Don's posts for at least three years, I doubt highly he has not accurately quoted the code in this thread.

Can you be more specific about what you feel is 'not accurate'?

Bob




[This message has been edited by iwire (edited 12-03-2005).]

Paul, not trying to answer for Don, but 210.12 has already been quoted, go back and read the earlier posts.

BTW, you never did answer Iwire's question posted on 11-20-2005 at 05:34 AM did you?

If you did I missed it.

Roger

[This message has been edited by Roger (edited 12-03-2005).]

I am sure Roger is talking about this question.


Bob