Chase nipple over 250V?

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rhovee

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I am sure this has gotten beaten to death already, but I currently in a disagreement with my boss. He thinks you can put two 12x12 boxes together and use a chase nipple with a locknut on the inside of one box and be legal. I tried explaining to him that sandwhiching 2 pieces of metal yo eachother without using locknuts is not going to mechanically tie them together. What are your thoughts? Would this be in the whitebook?
 
rhovee said:
I am sure this has gotten beaten to death already, but I currently in a disagreement with my boss. He thinks you can put two 12x12 boxes together and use a chase nipple with a locknut on the inside of one box and be legal. I tried explaining to him that sandwhiching 2 pieces of metal yo eachother without using locknuts is not going to mechanically tie them together. What are your thoughts? Would this be in the whitebook?
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No, he is wrong. Both boxes would still need individual supporting just like any other box. Change the chase nipple to a 2" long piece of EMT and changes nothing, you still need to properly support the boxes.
 
rhovee said:
I am sure this has gotten beaten to death already, but I currently in a disagreement with my boss. He thinks you can put two 12x12 boxes together and use a chase nipple with a locknut on the inside of one box and be legal. I tried explaining to him that sandwhiching 2 pieces of metal yo eachother without using locknuts is not going to mechanically tie them together. What are your thoughts? Would this be in the whitebook?
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Isn't this exactly how a chase nipple works?
 
rhovee said:
I am sure this has gotten beaten to death already, but I currently in a disagreement with my boss. He thinks you can put two 12x12 boxes together and use a chase nipple with a locknut on the inside of one box and be legal. I tried explaining to him that sandwhiching 2 pieces of metal yo eachother without using locknuts is not going to mechanically tie them together. What are your thoughts? Would this be in the whitebook?
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Would the chase nipple be supporting either box or just allowing wires to be passed from one box to another?
 
The chase nipple is for running the wires through, not a support. I always thought it was ok to do for below 250v. What we did was set a 24x24 on top of the MSB and then shut power down and spliced in the box to our feeders. We punched the box and MSB And used a chase nipple between them. It doesn't seem like the two enclosures are
Bonded together using this installation.
 
Truthfully I am not sure chase nipples are listed for grounding for any voltage.

There is nothing in the code regarding chase nipples used over 250 volts.
 
rhovee said:
I am sure this has gotten beaten to death already, but I currently in a disagreement with my boss. He thinks you can put two 12x12 boxes together and use a chase nipple with a locknut on the inside of one box and be legal. I tried explaining to him that sandwhiching 2 pieces of metal yo eachother without using locknuts is not going to mechanically tie them together. What are your thoughts? Would this be in the whitebook?
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So are you saying that you think there should be 2 locknuts between the 2 boxes? And not just a chase nipple with 1 locknut in 1 of the boxes?
 
Unless the paint is removed on the j-box with the smooth side of the chase nipple I see an issue with 250.12

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 continuity or be connected by means of fittings designed so as to make such removal unnecessary.
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iwire said:
Unless the paint is removed on the j-box with the smooth side of the chase nipple I see an issue with 250.12
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Yeah, never thought about that. If it is a painted surface that would be a problem.
 
It just seemed like the enclosure with the locknut would be grounded to the chase nipple but the box with the collard end would not be touching any metal. What about using rigid coupling with two chase nipples between panels? The reason i ask is because i have been called on both and not called on both. Just getting some ideas....But i do agree that if the paint was removed it would make it grounded.
 
What about a close nipple and (4) locknuts? That should ground things nicely.


SceneryDriver
 
rhovee said:
It just seemed like the enclosure with the locknut would be grounded to the chase nipple but the box with the collard end would not be touching any metal. What about using rigid coupling with two chase nipples between panels? The reason i ask is because i have been called on both and not called on both. Just getting some ideas....But i do agree that if the paint was removed it would make it grounded.
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I've used chase nipples and lock nuts, rigid couplings with chase nipples too; 1/2" on up to 2 1/2" with no green wire pulled.... never gave it a second thought.
 
I don't see how a chase nipple used with one locknut is a problem since that's how it's designed. The paint issue that Bob mentioned is another matter. For what it's worth according to the wording of 300.4(G) a chase nipple cannot be used with conductors #4 or larger since one side does not have an insulating material.
 
rhovee said:
I am sure this has gotten beaten to death already, but I currently in a disagreement with my boss. He thinks you can put two 12x12 boxes together and use a chase nipple with a locknut on the inside of one box and be legal. I tried explaining to him that sandwhiching 2 pieces of metal yo eachother without using locknuts is not going to mechanically tie them together. What are your thoughts? Would this be in the whitebook?
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You are talking about "Electrically'" connected not mechanically.
 
infinity said:
I don't see how a chase nipple used with one locknut is a problem since that's how it's designed. The paint issue that Bob mentioned is another matter. For what it's worth according to the wording of 300.4(G) a chase nipple cannot be used with conductors #4 or larger since one side does not have an insulating material.
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That's an interesting point. For conductors over #4 I guess you would have to use a listed plastic insert or grommet.
 
SceneryDriver said:
What about a close nipple and (4) locknuts? That should ground things nicely.


SceneryDriver
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A bonding jumper between enclosures works as well. You have 3 things that need bonded, enclosure A, enclosure B and the raceway with associated fittings. So if enclosure a is bonded, the locknut on enclosure A side will bond the nipple, but enclosure B with teh "chase nipple" end may not be bonded if painted surfaces are involved, you can either remove necessary paint or use a bonding jumper to ensure enclosure B is bonded - that is how I see it. A close nipple with 4 locknuts does remove the need for the bonding jumper, but also means the two enclosures are not in same position as they are with the chase nipple connecting them together. Sometimes that difference in the space between is very important to the installation.

infinity said:
For what it's worth according to the wording of 300.4(G) a chase nipple cannot be used with conductors #4 or larger since one side does not have an insulating material.
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I agree that is what is written, I also think that wording needs changes and have a feeling the intent there is not to prohibit the use of a chase nipple - but I could be wrong. That said I have used chase nipples for conductors #4 or larger many times and have never been called out on this by an inspector. But it is no different then the earlier mentioned driving over the speed limit doesn't mean you will always get a ticket for it.
 
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