Chase Nipples and #4 and Larger Conductors

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infinity

infinity

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Someone recently told me that you cannot use a chase nipple with a #4 or larger conductor since the requirement is that the chase nipple would need a insulating bushing on each side. Anyone ever hear of this? Here's the relevant section:

300.4(G) Insulated Fittings. Where raceways contain 4 AWG or larger insulated circuit conductors and these conductors enter a cabinet, box, enclosure, or raceway, the conductors shall be protected by a substantial fitting providing a smoothly rounded insulating surface, unless the conductors are separated from the fitting or raceway by substantial insulating material that is securely fastened in place.
Exception: Where threaded hubs or bosses that are an integral part of a cabinet, box, enclosure, or raceway provide a smoothly rounded or flared entry for conductors.
Conduit bushings constructed wholly of insulating material shall not be used to secure a fitting or raceway. The insulating fitting or insulating material shall have a temperature rating not less than the insulation temperature rating of the installed conductors
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Depending on the interpertation of the exception....the flared, smoothly rounded end of the chase nipple qualifies. The 'flared' end is an integral part of the chase nipple.
 
John Arendt said:
Depending on the interpretation of the exception....the flared, smoothly rounded end of the chase nipple qualifies. The 'flared' end is an integral part of the chase nipple.
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The way it's written it sounds like the "smoothly rounded or flared entry" only applies to threaded hubs or bosses.
 
" enclosure, or raceway provide a smoothly rounded or flared entry for conductors."

A chase nipple, or nipple is a raceway, IMHO.


A 'Boss' ? hmmm,... something that is impressed/indented??
 
John Arendt said:
" enclosure, or raceway provide a smoothly rounded or flared entry for conductors."

A chase nipple, or nipple is a raceway, IMHO.


A 'Boss' ? hmmm,... something that is impressed/indented??
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Would that not be an embossed object?

I dunno, but I cannot attach the verb directly to the noun without a little more definition.

An embossed object is a boss?
 
The issue here is the word insulating in the requirement. Certainly a close nipple with a plastic bushing on each end would meet the insulating part. Use a chase nipple with insulating on only one end and that's where the problem begins. I've done this a hundred times without even a thought but now an inspector is telling me that, in his opinion, it's a violation if the conductors are larger than #6.
 
IMO the insulating bushing is required for the protection of the conductor(s) from damage by the "sharp" edge(s) of a nipple. Since the chase nipple has a smooth, flared end then there would not be anything "sharp" on the one end, thus no need for insulating bushing.
 
infinity said:
The issue here is the word insulating in the requirement. Certainly a close nipple with a plastic bushing on each end would meet the insulating part. Use a chase nipple with insulating on only one end and that's where the problem begins. I've done this a hundred times without even a thought but now an inspector is telling me that, in his opinion, it's a violation if the conductors are larger than #6.
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That's pretty interesting, I know T & B makes insulated chase nipples, maybe just for this requirement.
 
infinity said:
The issue here is the word insulating in the requirement. Certainly a close nipple with a plastic bushing on each end would meet the insulating part. Use a chase nipple with insulating on only one end and that's where the problem begins. I've done this a hundred times without even a thought but now an inspector is telling me that, in his opinion, it's a violation if the conductors are larger than #6.
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The first qualifier of the requirement is 4 AWG or larger conductors in a raceway and entering an enclosure or such. Is a chase nipple a raceway or just a fitting???
 
I found this inspector's comments interesting since it seems to be splitting hairs, but the way I read the requirement it appears that you need an insulating material on both sides of the chase nipple. Sounds rather silly since I can have a smooth rounded metal hub and no insulating material is required.
 
Smart $ said:
The first qualifier of the requirement is 4 AWG or larger conductors in a raceway and entering an enclosure or such. Is a chase nipple a raceway or just a fitting???
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I think you nailed it but I also know that would upset many inspectors, I can hear it now 'But the intent ....
 
iwire said:
I think you nailed it but I also know that would upset many inspectors, I can hear it now 'But the intent ....
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My initial thought as well. So is a chase nipple a fitting or a raceway? If it's a fitting then would it even require a bushing on the threaded portion of the chase nipple?
 
infinity said:
Someone recently told me that you cannot use a chase nipple with a #4 or larger conductor since the requirement is that the chase nipple would need a insulating bushing on each side.
Click to expand...

I think I am overlooking something here. Why wouldn't you be able to use a chase nipple with #4 or larger? How would the requirement of an insulating bushing on each side disqualify the use of the nipple?
 
infinity said:
My initial thought as well. So is a chase nipple a fitting or a raceway? If it's a fitting then would it even require a bushing on the threaded portion of the chase nipple?
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In the UL White Book index I found this

Chase Nipples (see Conduit Fittings
(DWTT)) ............................................................. 111
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and

Nipples, Chase (see Conduit Fittings
(DWTT)) ............................................................. 111
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Seems like they are fittings.
 
Smart $ said:
The first qualifier of the requirement is 4 AWG or larger conductors in a raceway and entering an enclosure or such. Is a chase nipple a raceway or just a fitting???
Click to expand...

So an EMT connector, a flexible conduit connector, a PVC male adapter, or any other raceway termination fitting is also not a raceway but is a fitting. You should not need a bushing on any of those either if that is the substantiation. Threaded RMC or IMC yes.
 
kwired said:
So an EMT connector, a flexible conduit connector, a PVC male adapter, or any other raceway termination fitting is also not a raceway but is a fitting. You should not need a bushing on any of those either if that is the substantiation. Threaded RMC or IMC yes.
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That seems to be where this is going. :huh:
 
kwired said:
So an EMT connector, a flexible conduit connector, a PVC male adapter, or any other raceway termination fitting is also not a raceway but is a fitting. You should not need a bushing on any of those either if that is the substantiation. ...
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Those fittings are designed to be used in tandem with raceway. A chase nipple is not.
 
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