3R enclosure, no grounding provision

[mark32]

I just purchased an 8x8 3R rated pull box and an 8x8 indoor pull box. The back wall of the indoor box is stamped and drilled for a ground screw, the 3R box does not. Is there an issue if I drill and tap my own hole in the back wall of the 3R box?

 

[K8MHZ]

I just purchased an 8x8 3R rated pull box and an 8x8 indoor pull box. The back wall of the indoor box is stamped and drilled for a ground screw, the 3R box does not. Is there an issue if I drill and tap my own hole in the back wall of the 3R box?

I don't suggest tapping. You really should use a field grounding kit, like this one:

View attachment 6463

http://www.automationdirect.com/adc/Shopping/Catalog/Enclosures/Metal/Accessories/Misc/WGNDKT

 

[mark32]

I don't suggest tapping. You really should use a field grounding kit, like this one:

View attachment 6463

http://www.automationdirect.com/adc/Shopping/Catalog/Enclosures/Metal/Accessories/Misc/WGNDKT

Alright, so you're saying I should bolt this lug to the enclosure instead of tapping a 10-32 to it. Anything in particular wrong with tapping?

 

[Cow]

I drill/tap or nut/bolt these things all the time. I've never used a special "grounding kit" unless it came with the box. I use a little grinder to remove the paint under the lug since the inspector checks for that.

By the way, from what I've seen the Hoffman 3R boxes don't have the ground screw hole, but the Cooper B-Line 3R boxes do, if you have a choice.

 

[K8MHZ]

Alright, so you're saying I should bolt this lug to the enclosure instead of tapping a 10-32 to it. Anything in particular wrong with tapping?

I think it has something to do with the amount of threads that would be made being insufficient for the purpose.

 

[ritelec]

Drilled and tapped here, also nut and bolted.

Just have me wondering though, I never heard of a thread count needed...........but lets say if you are installing a ground bar in a panel or bonding the neutral........

the hole thats being used to screw into is not just a tapped hole in the sheet metal......the holes been kinda peened back to create more thread.

Never thought about this. Interesting.

 

[K8MHZ]

Drilled and tapped here, also nut and bolted.

Just have me wondering though, I never heard of a thread count needed...........but lets say if you are installing a ground bar in a panel or bonding the neutral........

the hole thats being used to screw into is not just a tapped hole in the sheet metal......the holes been kinda peened back to create more thread.

Never thought about this. Interesting.

Look at 250.8(A) You have to have at least two full threads, or be secured by a nut. For a 10-32 that means a minimum of 1/16 of an inch of thread bearing metal.

 

[ritelec]

Thanks K8MHZ !

1/16 of an inch.........did you get that mark 32?

???? Would you know of any particular minimum size screw or bolt for a ground K8MHZ.......eg. 6 or 8/32 ???


May I call you K, K8MHZ?

As I type your handle, I keep getting David Bowies song TVC15 in my head.


Rich

 

[mark32]

Got it ritelec, I'll measure the enclosure and see how thick it is and go from there. On another note, cow brings up the topic of removing the surface covering of an enclosure that would end up underneath a field installed lug. I don't disagree, however, when you bond an elevated neutral bar in a main panel with a screw, what is happening there? The same thing that's happening, in my eyes, when a lug/bar is installed on a non sanded/grinded surface. All you have contacting that elevated neutral bar is the head of the screw which in turn is just contacting the threaded hole of the panel. Same thing no?

 

[ritelec]

Yeah, thats pretty wack.....

Guess it's a manufacturer thing and beyond us.

So many must be this and that.........then for the most part your working with stuff thats engineered and designed to be held on by a pubic hair.

Lotta overpriced junk out there.

 

[ActionDave]

Got it ritelec, I'll measure the enclosure and see how thick it is and go from there. On another note, cow brings up the topic of removing the surface covering of an enclosure that would end up underneath a field installed lug. I don't disagree, however, when you bond an elevated neutral bar in a main panel with a screw, what is happening there? The same thing that's happening, in my eyes, when a lug/bar is installed on a non sanded/grinded surface. All you have contacting that elevated neutral bar is the head of the screw which in turn is just contacting the threaded hole of the panel. Same thing no?

Here's the section.

250.12 Clean Surfaces
Nonconductive coatings (such as paint, lacquer, and enamel)
on equipment to be grounded shall be removed from threads
and other contact surfaces to ensure good electrical continu-
ity or be connected by means of fittings designed so as to
make such removal unnecessary.

A manufactured panel would comply with the last sentence.

I tap threads and add a star washer and a nut. Usually I don't scrape the paint. I think it counts too.

 

[hurk27]

Yeah, thats pretty wack.....

Guess it's a manufacturer thing and beyond us.

So many must be this and that.........then for the most part your working with stuff thats engineered and designed to be held on by a pubic hair.

Lotta overpriced junk out there.

While we may think so, there has been many scientific test that has set many of the standards we go by, and whether it is UL, NEC or IEE that set these standards there is much to be learned by them, many don't think about the available fault current even in a 15 amp branch circuit, but if it is close enough to the panel feeding it, the available fault current can be in the hundreds of amps, or even in the thousands of amps for larger circuits, I have see the results and a few fires caused by this very issue, one was a 60 amp subpanel about 4' away from the main service, the only bond was a #8/32 screw tapped into the panel holding a lug to the panel.

If you look more closely at that lug kit in the post above you will see a large star washer along with two small ones, it is designed to bite through the paint when the screw and nut is tightened, if a star washer is not used then the paint needs to be removed. See 250.12 I'm not sure where to find it in UL but I think I remember the 2 or more engaged threads was from UL or IEE.

Almost all grounding bar kits are designed to use two or more screws (unless it is a very small one) to mount it and come with the star washers.

 

[ritelec]

the available fault current can be in the hundreds of amps, or even in the thousands of amps for larger circuits,

Thankfully, I've never experienced these faults (shorts).......but have found a new respect for it and its existence.......burns, maim, vaporize. (KNOCKING ON WOOD).

As far as my post, I know the manufacture must put a great deal into the design and manufacturing of the equipment. But you must admit.......at times......it's ka ka.


Quickly, My older brother also does this. He had mentioned once installing a 480v disconnect. There was a short somewhere and the disconnect flew off the wall in a clock wise rotation.......

No injuries or vaporizations ........... but I found it interesting how it was thrown with a spin to it.


I learned a bit from this post.....thank you all!

 

[kwired]

Got it ritelec, I'll measure the enclosure and see how thick it is and go from there. On another note, cow brings up the topic of removing the surface covering of an enclosure that would end up underneath a field installed lug. I don't disagree, however, when you bond an elevated neutral bar in a main panel with a screw, what is happening there? The same thing that's happening, in my eyes, when a lug/bar is installed on a non sanded/grinded surface. All you have contacting that elevated neutral bar is the head of the screw which in turn is just contacting the threaded hole of the panel. Same thing no?

Thankfully, I've never experienced these faults (shorts).......but have found a new respect for it and its existence.......burns, maim, vaporize. (KNOCKING ON WOOD).

As far as my post, I know the manufacture must put a great deal into the design and manufacturing of the equipment. But you must admit.......at times......it's ka ka.


Quickly, My older brother also does this. He had mentioned once installing a 480v disconnect. There was a short somewhere and the disconnect flew off the wall in a clock wise rotation.......

No injuries or vaporizations ........... but I found it interesting how it was thrown with a spin to it.


I learned a bit from this post.....thank you all!

Swap any two leads and it will rotate the other direction

 

[K8MHZ]

Thanks K8MHZ !

1/16 of an inch.........did you get that mark 32?

???? Would you know of any particular minimum size screw or bolt for a ground K8MHZ.......eg. 6 or 8/32 ???


May I call you K, K8MHZ?

As I type your handle, I keep getting David Bowies song TVC15 in my head.


Rich

No minimum size comes to mind. Maybe common sense would be needed to decide instead of the book. :angel:

You can call me K, you can call me Ray, you can call me J, just don't call me Johnson.

David Bowie side note: Iggy Pop (James Newell Osterberg, Jr.) was born in the same town I was. His birth certificate is at the county clerk's office. I still live in the same county. I have been in the actual room that Iggy was born in. The hospital he was born in is now our Red Cross building and I have been in every room of it. We have a ham radio station there, W8NVY.

 

[ritelec]

You can call me K, you can call me Ray, you can call me J, just don't call me Johnson.

That's good..................showing your age (and I guess I am too since I remember him)

David Bowie side note: Iggy Pop (James Newell Osterberg, Jr.) was born in the same town I was. His birth certificate is at the county clerk's office. I still live in the same county. I have been in the actual room that Iggy was born in. The hospital he was born in is now our Red Cross building and I have been in every room of it. We have a ham radio station there, W8NVY.

Did I ever tell you about the time I was possessed by Jimi Hendrix??? Seriously.......it was a quick thing at an apartment he had lived in, in the village NYC. For true.



Funny kwired...............didn't even think of that.

Question.... how to change rotation of spinning disconnects flying off walls? nice... :thumbsup:

 

[K8MHZ]

That's good..................showing your age (and I guess I am too since I remember him)


Did I ever tell you about the time I was possessed by Jimi Hendrix??? Seriously.......it was a quick thing at an apartment he had lived in, in the village NYC. For true.

Jimi Hendrix? No way. Jimi wasn't at all like that. You were probably possessed by a Jimi Hendrix impersonator.

 

[templdl]

I worked for a transformer manufacturer wh did the same thing, they didn't have a clue that grounding an enclosure was required. When providing a N3R enclosure they put the grounding stud on the ouside of the enclosure and not in the terminal compartment. OK, conduit is run and secured through into the wiring compartment, wire is pulled into the wiring compartment with the EGC. Now, alll of the wires are in the compartment, where did I say that grounding stud was? On the outside of the enclosure because it was easier to add there.
I had to just shake my head.
Grounding studs should be welded in place within the terminal compartment and can be adding as part of an order. The only catch is that you have to know that the enclosure doesn't come standard with one unless you remember to ask, and that the wholesaler of manufacturer's rep probably doesn't have a clue.

If there are grounding provisions provided how is it going to be possible to add one and still comply with UL? The manufacturer must have a UL listed modification proceedure in place in order to comply with NEC Art 110.3
(B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

Even though drilling and tapping an enclosure would make sense is it a proceedure that is included with the installation instruction that would be a part of the listing and labeling of the product?

 

[K8MHZ]

I worked for a transformer manufacturer wh did the same thing, they didn't have a clue that grounding an enclosure was required. When providing a N3R enclosure they put the grounding stud on the ouside of the enclosure and not in the terminal compartment. OK, conduit is run and secured through into the wiring compartment, wire is pulled into the wiring compartment with the EGC. Now, alll of the wires are in the compartment, where did I say that grounding stud was? On the outside of the enclosure because it was easier to add there.
I had to just shake my head.
Grounding studs should be welded in place within the terminal compartment and can be adding as part of an order. The only catch is that you have to know that the enclosure doesn't come standard with one unless you remember to ask, and that the wholesaler of manufacturer's rep probably doesn't have a clue.

If there are grounding provisions provided how is it going to be possible to add one and still comply with UL? The manufacturer must have a UL listed modification proceedure in place in order to comply with NEC Art 110.3
(B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

Even though drilling and tapping an enclosure would make sense is it a proceedure that is included with the installation instruction that would be a part of the listing and labeling of the product?

The kit I showed was part of the nomenclature from a 3R box. The nomenclature said that unless the box was made to CA specs, there would be no grounding provisions an if ground provision was needed, you were supposed to use the kit, which didn't come with the box, and it had a P/N and a link.