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Posted By: triple close nipple use - 04/02/09 03:48 AM
Can a close nipple be used to attach something such as a rigid coupling or a condulet to a box (junction, panel, etc.)? If not, is it a grounding or listing problem?

Thanks.
Posted By: renosteinke Re: close nipple use - 04/02/09 04:47 AM
I don't see anyproblem doing that.
Posted By: George Little Re: close nipple use - 04/02/09 12:34 PM
I agree with you Reno, I used to do it all the time when I was wearing the tools. There could be a case where the stricter bonding requirements are in place, say for over 250v. to ground where it might be suspect but normally an installation like this when made up tight is pretty hard to beat and guys do it routinely.
Posted By: triple Re: close nipple use - 04/03/09 02:53 AM
Another master electrician claims that close nipples cannot be used in such a way. Perhaps it is because close nipples do not have tapered threads or that they do not screw in far enough to contact enough threads??????
Posted By: frenchelectrican Re: close nipple use - 04/03/09 05:37 AM
Originally Posted by triple
Another master electrician claims that close nipples cannot be used in such a way. Perhaps it is because close nipples do not have tapered threads or that they do not screw in far enough to contact enough threads??????


All you have to becarefull with close nipples pipe is get correct tapered thread instead of straght cut threaded pipe that can raise some issue.

However., Both America and European both done the same thing for very long time and no issue arised with this and just heed with bonding issue if your local area do required it.

Merci,Marc
Posted By: gfretwell Re: close nipple use - 04/03/09 06:49 AM
I would think you would want straight cut threads so the only thing stopping the lock nut is compressing/cutting into the cabinet material. You certainly wouldn't want a tapered thread to lock up in the condolet with too much taper left out for the lock nut to get all the way into contact with the cabinet before it locks up.
I thought that was why we use straight threads.
Posted By: electure Re: close nipple use - 04/03/09 01:47 PM
A CLOSE nipple is tapered on both ends

[Linked Image]

A CHASE nipple is a straight thread

[Linked Image]


I have to wonder which one the OP is discussing



Posted By: gfretwell Re: close nipple use - 04/03/09 04:56 PM
For the purposes of attaching an LB to a cabinet a chase nipple or a box connector is a better choice.
I do believe a "close nipple" made up from a short section of straight thread pipe is also appropriate.
If you use a RMC nipple, like the one picture above, I think you also need to use 2 locknuts, one inside and one outside.
Posted By: George Little Re: close nipple use - 04/03/09 10:27 PM
Greg- I would agree with you and add that if we are talking about an LB, I think a Chase nipple made up wrench tight is a good connection but if you are talking about a SLB there could be a debate. The body of an SLB may interfere with a good connection. In either case the close nipple w/ lock nuts is a better choice. For those who would prefer a Close nipple, tell me what would yo use a Chase for if anything?
Posted By: renosteinke Re: close nipple use - 04/04/09 02:29 AM
Electure,thanks for the pics! I was thinking "chase nipple,' but the OP dod say 'close nipple.'

A few other details need to be addressed.

First of all, many folks make their own short nipplez by cutting off a length of 'running thread.' While the NEC is silent as to using running thread into conduit bodies, it prohibits using running thread with threaded couplings.

"Chase nipples" come in different lengths, and the threads are straight (not tapered). This brings up two issues.

The nipples cannot be so long that they 'bottom out' before everything is tight.

Plus .... while the 'cheap' conduit bodies have straight threads, iron ones have tapered threads. Thus, it is possible that you will not be able to properly thread some fittings into some conduit bodies.

A chase nipple provides a nice, tapered throat for the wires to enter the pipe. A close nipple, by way of contrast, requires multiple lock nuts and a plastic bushing. I typically use them in combination with a threaded coupling, as when I have to attach a stem-mounted light to a box; I am not always able to rotate the fixture, and the coupling makes a much more secure mounting than attaching the stem to the box directly.
Posted By: gfretwell Re: close nipple use - 04/04/09 03:52 AM
If you couldn't use straight thread into a conduit body you couldn't use an EMT connector.
I agree jointing RMC is more like plumbing but everything else is a simple, compression, "nut and bolt" situation.
If I had a concern about the "chase nipple/LB" joint it would be that there wasn't a star washer in the joint ... but I have a hard time making a code case unless it was some obscure "paint" reference. A short piece of straight thread with a hard biting lock nut would make me feel better. I look for reasonable fault paths in raceways, even with a green wire. You don't want hot pipe. I know the code really only gets serious in service raceways and fire pumps.
Posted By: gfretwell Re: close nipple use - 04/04/09 04:43 AM
In retrospect I bet the tapered thread LBs are listed explosion proof.
Posted By: electure Re: close nipple use - 04/04/09 03:27 PM
The tapered threads of some conduit bodies are not intended for use with EMT fittings,chase nipples, or any straight thread fitting, just IMC/RMC, and some are not listed for use as explosion proof fittings.

http://www.appletonelec.com/pdf/A-2-3-4-5-6-15.pdf

http://www.o-zgedney.com/PDF/OZG_AB%5B1%5D.pdf






Posted By: gfretwell Re: close nipple use - 04/04/09 05:50 PM
It is interesting that Appleton starts out saying "Rigid steel, Rigid aluminum IMC and EMT", then drops EMT when they get to the specifics.
How would an inspector know which conduit bodies are listed for EMT?
Posted By: renosteinke Re: close nipple use - 04/05/09 12:55 AM
Greg, just look at the connectors. If there are lots of threads sticking out of the body, the connector doesn't fit.
Posted By: gfretwell Re: close nipple use - 04/05/09 01:45 AM
if it was made up wrench tight the objective of an effective fault path would be met tho. wink
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