Chase Nipples and #4 and Larger Conductors

[infinity]

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

 

[John Arendt]

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.

 

[infinity]

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.

The way it's written it sounds like the "smoothly rounded or flared entry" only applies to threaded hubs or bosses.

 

[jumper]

The way it's written it sounds like the "smoothly rounded or flared entry" only applies to threaded hubs or bosses.

What is a "boss"?

 

[John Arendt]

" 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??

 

[jumper]

" 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??

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?

 

[infinity]

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.

 

[1793]

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.

 

[elohr46]

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.

That's pretty interesting, I know T & B makes insulated chase nipples, maybe just for this requirement.

 

[Smart $]

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.

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???

 

[infinity]

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.

 

[iwire]

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 think you nailed it but I also know that would upset many inspectors, I can hear it now 'But the intent ....

 

[infinity]

I think you nailed it but I also know that would upset many inspectors, I can hear it now 'But the intent ....

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?

 

[M4gery]

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.

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?

 

[iwire]

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?

In the UL White Book index I found this

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

and

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

Seems like they are fittings.

 

[infinity]

In the UL White Book index I found this



and



Seems like they are fittings.

So in that case they do not require a bushing at all according to 300.4(G).

 

[kwired]

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???

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.

 

[infinity]

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.

That seems to be where this is going. :huh:

 

[Smart $]

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. ...

Those fittings are designed to be used in tandem with raceway. A chase nipple is not.

 

[iwire]

Those fittings are designed to be used in tandem with raceway. A chase nipple is not.

I agree with you, but does an EMT raceway enter an enclosure or does just the fitting.