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plumbing nipples with rigid conduit.

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reyamkram

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Discussion starter · #1 ·
Where I work I keep commig across place where there is a mixture of rigde conduit with a plumbing nipples,
and some are in a hazrdous location, where in NFPA 70 or 79, can I find this is violation or unsafe practices.
I do not is see any wiring methods in ch 3 , wher it is ok.

Thank you. for any and all information.
 
#4 ·
I think the only argument could be that black pipe isn’t listed in chapter three. So no uses permitted or not permitted. Otherwise they are the same thread. There is no difference between a galvanized plumbing nipple and an electrical nipple. It’s the couplings and hubs that are different
 
#5 ·
bill39 said:
Practically speaking, as long as the plumbing nipple has tapered threads, properly reamed, and is galvanized it will be Ok.

How it can be determined if it came from the plumbing department or the electrical department would be difficult to prove.
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I was on the supply side for 16 years.. all our nipples looked the same as the plumbing ones.
 
#8 ·
Dennis Alwon said:
I believe electric threads are tapered while plumbing threads aren't
Click to expand...
Plumbing threads are tapered, too (NPT)

bill39 said:
I believe electrical threads on pipe are tapered & the threads inside electrical couplings are not tapered. Someone here, please correct me if I’m wrong.
Click to expand...
That's right, couplings are NPSM (national pipe straight mechanical) which is for mechanical joining not a watertight seal.
 
#9 · (Edited)
My understanding was the inside of RMC was smooth, so, the wire isn't damaged. Also, does RIGID make separate electrician & plumber thread dies?
 
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#10 ·
On some female fittings there is a step that is chamfered one the electrical version but not the plumbing version.

At least in PVC the plastic pipe has a UL stamp that is different for electrical use. It’s still schedule 40.

In think you’re thinking if NPST which is straight thread not tapered. Not used in plumbing.
 
#12 ·
I saw this done on a few occasions during my apprenticeship. It's usually the result of p*ss-poor planning or a supposed emergency. Anyway, my journeyman told me to spray the schedule 80 black pipe and the conduit junctions with a flat gray paint (used for touching up panels). From a distance or to the untrained eye, it was hard to see. To be fair, he said if forced to do this, add a ground wire instead of relying of the conduit to serve as ground. Over time, galvanic action will corrode and ultimately break the joint. He wasn't too worried. He knew he'd be in the ground before that happened.
 
#13 ·
If they used galvanized plumbing nipples, There will be no way to tell from the outside. The threads and pipe/conduit are the same. Only differences are on the inside. Electrical conduit nipples are supposed to be smooth with the internal weld removed or smoothed out, both should be reamed. Some brands of RMC nipples have a smooth finish on the outside and some don't. Some have an obvious weld that is somewhat smoothed or removed from protruding and some not so much. On longer nipples RMC will have listing stickers, but not all the time.

They both use the same NPT threads on the nipples. Electrical couplers are not tapered to allow the conduit to thread in further for stronger lateral support, but is not water tight like a plumbing/tapered coupler.
 
#16 · (Edited)
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#17 ·
reyamkram said:
Where I work I keep commig across place where there is a mixture of rigde conduit with a plumbing nipples,
and some are in a hazrdous location, where in NFPA 70 or 79, can I find this is violation or unsafe practices.
I do not is see any wiring methods in ch 3 , wher it is ok.

Thank you. for any and all information.
Click to expand...
Non issue.
Over thinking if just a close nipple.

Pipe or longer nipples might matter.
Insides of conduit and pipe are different.

Electrical has a smooth interior, plumbing has a weld line.
 
#18 ·
reyamkram said:
Where I work I keep commig across place where there is a mixture of rigde conduit with a plumbing nipples,
and some are in a hazrdous location, where in NFPA 70 or 79, can I find this is violation or unsafe practices.
I do not is see any wiring methods in ch 3 , wher it is ok.

Thank you. for any and all information.
Click to expand...
What your referring to is; Chapter 3/ Article 344

344.6 Listing Requirements. RMC, factory elbows and couplings, and associated fittings shall be listed.

Part III Construction Specifications.
344.100 Construction, RMC shall be made of one of the following:

(1) *Steel with protective coatings.
(2) Aluminum
(3) Red brass
(4) Stainless steel.

*I've never seen plumbing pipe w/ protective coating, on inside or the outside of the nipple.

Hope this helps. Have a safe day..
 
#19 ·
Dell3c said:
What your referring to is; Chapter 3/ Article 344

344.6 Listing Requirements. RMC, factory elbows and couplings, and associated fittings shall be listed.

Part III Construction Specifications.
344.100 Construction, RMC shall be made of one of the following:

(1) *Steel with protective coatings.
(2) Aluminum
(3) Red brass
(4) Stainless steel.

*I've never seen plumbing pipe w/ protective coating, on inside or the outside of the nipple.

Hope this helps. Have a safe day..
Click to expand...
The protective coating might be galvanize. I don't know for sure though.
 
#20 ·
Bird dog said:
My understanding was the inside of RMC was smooth, so, the wire isn't damaged. Also, does RIGID make separate electrician & plumber thread dies?
Click to expand...
Yes they make straight threads dies. That is what I was always told to use in our threaders, 2x the cost back then.
 
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