250.92(B)(3)

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Pinnie

Senior Member
Location
Ohio
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Commercial Electrician
Reading through 250.92. I find the text easy to understand, except (B)(3). I read through another forum that discussed the topic to conclusion, which was that threadless couplings and connectors are acceptable for use of bonding service raceway to service raceway, but not service raceway to enclosure. https://forums.mikeholt.com/threads/article-250-92-b-3-nec.38369/

I don’t disagree that enhance bonding should be required from service raceways to enclosures, but the text confuses me. I don’t see the how we get that interpretation.

My thought is simply that a threadless connector must be a different style of connector than then standard emt connector. One without threads at all.
 
Pinnie said:
I read through another forum that discussed the topic to conclusion, which was that threadless couplings and connectors are acceptable for use of bonding service raceway to service raceway, but not service raceway to enclosure.
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I this case the threadless connector entering the enclosure is no different than if RMC entered the enclosure. In either case the standard locknut is not sufficient (from a code perspective) to bond the raceway to the enclosure. So as mentioned in the other thread you've linked to the locknut that comes with the threadless connector cannot be the sole bonding method.
 
infinity said:
I this case the threadless connector entering the enclosure is no different than if RMC entered the enclosure. In either case the standard locknut is not sufficient (from a code perspective) to bond the raceway to the enclosure. So as mentioned in the other thread you've linked to the locknut that comes with the threadless connector cannot be the sole bonding method.
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What would be an example of a threadless connector? I have seen threadless couplings but not connectors.
 
Pinnie said:
What would be an example of a threadless connector? I have seen threadless couplings but not connectors.
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An EMT fitting. There is a thread on a different forum that discusses this in great detail. A few of the participants are regulars here. https://www.thebuildingcodeforum.co...nding-jumper-for-250-92-b-4.38846/post-309333

(Moderator: If I'm not supposed to post a link to another forum on this forum, please let me know/remove it. I don't want to cause trouble.)
 
infinity said:
I this case the threadless connector entering the enclosure is no different than if RMC entered the enclosure.
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Sure it is. With the threaded end of plain RMC entering an enclosure, you have two locknuts opposite each other, and UL 514(B) only requires mechanical testing on the locknut, no electrical testing. While with a threadless connector, you have the connector opposite a provided locknut, and the combination has been tested under UL 514(B) for resistance and current.

250.90(B)(3) plainly says that a threadless connector suffices for bonding at a service.

Cheers, Wayne
 
NEC Inspector said:
An EMT fitting. There is a thread on a different forum that discusses this in great detail. A few of the participants are regulars here. https://www.thebuildingcodeforum.co...nding-jumper-for-250-92-b-4.38846/post-309333

(Moderator: If I'm not supposed to post a link to another forum on this forum, please let me know/remove it. I don't want to cause trouble.)
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Here is wwhitneys post that claims all EMT fittings are threadless fittings.

“Per UL 514B "Conduit, Tubing, and Cable Fittings," a threadless fitting is "A fitting intended for use with nonthreaded rigid metal conduit, intermediate metal conduit, or electrical metallic tubing. So all EMT fittings are threadless fittings, and an EMT connector is a threadless connector. “

As a novice, it seems to me an EMT fitting is threaded.
 
My main issue is with the text, not that I have a hard opinion on what should be required.
 
Pinnie said:
What would be an example of a threadless connector? I have seen threadless couplings but not connectors.
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A threadless connector is one that replaces the threads on a conduit. Like this one.

rcc100kon.jpg


wwhitney said:
250.90(B)(3) plainly says that a threadless connector suffices for bonding at a service.
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I disagree. By using your logic an EMT connector could be used with a service raceway with a standard locknut.
 
Pinnie said:
Is that terminology misleading to you as it is to me?
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No. It replaces a thread. Someone can checked the listing but since EMT cannot be threaded an EMT connector is not a threadless connector. When you get over 2 inch it gets murky.
 
I just want to know how to bond a dang service lol now I have to look at ul listings. I’ll just bonding bush everything.
 
wwhitney said:
See post #6, an EMT connector is a threadless connector per the definition in UL 514(B).

Cheers, Wayne
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I can accept that that's why mentioned checking the listing. It just doesn't make much sense to me to call a fitting threadless when used on a raceway that cannot be threaded.
 
infinity said:
I can accept that that's why mentioned checking the listing.
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So does that mean you accept that say out of the bottom of a meter base an EMT connector with its included locknut complies by itself with 250.92(B)?

infinity said:
It just doesn't make much sense to me to call a fitting threadless when used on a raceway that cannot be threaded.
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Whereas I would expect that when a raceway can't be threaded, every fitting should be considered threadless, as it must rely on other means to connect to the raceway.

Cheers, Wayne
 
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