ECN Forum Forums Code Related Discussion NEC & other Code issues close nipple use

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.

I don't see anyproblem doing that.

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.

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

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.

A CLOSE nipple is tapered on both ends



A CHASE nipple is a straight thread




I have to wonder which one the OP is discussing

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.

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?

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.