Chase Nipples and #4 and Larger Conductors

[renosteinke]

Can't anyone tell the difference between a 'rule' and an 'exception?'

The 'rule' is that the wires must be protected by a rounded fitting; that is, the throat of a chase nipple is one of the very few places where this is found. The chase nipple complies with the rule.

The 'exception' is where the wires are further protected by a bushing or liner. Thus, we are allowed to add bushings to ordinary nipples, or the 'sharp' end of a chase nipple, to provide the protection we want.

 

[kwired]

Can't anyone tell the difference between a 'rule' and an 'exception?'

The 'rule' is that the wires must be protected by a rounded fitting; that is, the throat of a chase nipple is one of the very few places where this is found. The chase nipple complies with the rule.

The 'exception' is where the wires are further protected by a bushing or liner. Thus, we are allowed to add bushings to ordinary nipples, or the 'sharp' end of a chase nipple, to provide the protection we want.

That makes common sense, but the wording uses 'insulating' in the requirement.

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

You can use a chase to terminate RMC or IMC by butting a coupling to an enclosure and threading the chase into it from inside the enclosure.

 

[don_resqcapt19]

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

It doesn't matter...the section no longer says that the raceway has to enter the enclosure. It says where "these conductors enter the enclosure". That was changed in the 2008 code as a result of one of my proposals.

(G) Insulated Fittings. Where raceways contain 4 AWG or larger insulated circuit conductors, and these conductors enter a cabinet, a box, an enclosure, or a raceway, the conductors shall be protected by an identified fitting providing a smoothly rounded insulating surface, unless the conductors

are separated from the fitting or raceway by identified insulating material that is securely fastened in place.​

This makes the section cover all of the raceways, but still leaves a loophole for the chase nipple.​

 

[infinity]

It doesn't matter...the section no longer says that the raceway has to enter the enclosure. It says where "these conductors enter the enclosure". That was changed in the 2008 code as a result of one of my proposals.

This makes the section cover all of the raceways, but still leaves a loophole for the chase nipple.[/LEFT][/SIZE][/FONT][/SIZE][/FONT]

I think that this is the best answer we can get. The chase nipple has slipped through the cracks of this requirement.

For what it's worth the inspector made the EC take down the enclosure, rip out the chase nipple and install a close nipple with two bushings. :roll:

 

[Smart $]

... You can use a chase to terminate RMC or IMC by butting a coupling to an enclosure and threading the chase into it from inside the enclosure.

You can! But not a compliant installation.

Here's the compliant version: http://www.cooperindustries.com/con...viceentrance/hubs/hub_series_conduithubs.html

 

[sandsnow]

For what it's worth the inspector made the EC take down the enclosure, rip out the chase nipple and install a close nipple with two bushings. :roll:

I'm sure that inspector is a nice family man, but really making him rip it out? The guy is out of control.

If I was going to call that, I would have told him not to do it anymore and explain why.

 

[kwired]

You can! But not a compliant installation.

Here's the compliant version: http://www.cooperindustries.com/con...viceentrance/hubs/hub_series_conduithubs.html

What is not compliant? I have heard some say it is not acceptable for continuity of enclosure to raceway. If that is the case what can you use a chase nipple for?

Item in your link is not really much different other than it does have a gasket for wet locations, the straight vs tapered threads issue could come to play, but I'm willing to bet the threads on the hub are straight, on the box side especially.

 

[Smart $]

What is not compliant? I have heard some say it is not acceptable for continuity of enclosure to raceway. If that is the case what can you use a chase nipple for?

Item in your link is not really much different other than it does have a gasket for wet locations, the straight vs tapered threads issue could come to play, but I'm willing to bet the threads on the hub are straight, on the box side especially.

When used as you suggest in connecting a raceway, the throat is not insulated, as per the section we are discussing.

As for not being acceptable for continuity [bonding], I'd like to see authoritative documentation to that effect. Perhaps they do not provide continuity as sound as other methods, but that is a matter for another discussion.

Item in my link is made and listed specifically for the purpose. Additionally, it has an insulated throat. Can't tell from picture, but so noted in features. See picture here: http://www.plccenter.com/Shop/CROUSE HINDS/HUB10/FNFP?source=GoogleShopping AFAIK, the hub end has tapered threads. So what if the box end has straight threads??? There's a good chance the bushed nipple has straight threads also.

 

[kwired]

When used as you suggest in connecting a raceway, the throat is not insulated, as per the section we are discussing.

I guess I thought you were trying to say it was not compliant for other reasons, as this is more less the topic of the thread. So do you agree that the coupling - chase nipple used as a box termination is compliant if contained conductors are smaller than 4 AWG?

 

[Smart $]

... So do you agree that the coupling - chase nipple used as a box termination is compliant if contained conductors are smaller than 4 AWG?

I know of no authoritative information which repudiates compliance.