Outside corner 90 bend emt wet location options

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tortuga said:
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There is no code compliant (2014 NEC 358.6) way in a wet or damp location to connect a rain tight EMT connector (straight threads) to a conduit body like an LB or a bell box threaded hub (tapered threads).
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Not directly, but using a raintight EMT RMC combination coupling (Post #4) and an RMC [close] nipple is an easy fix.
 
Smart $ said:
Not directly, but using a raintight EMT RMC combination coupling (Post #4) and an RMC [close] nipple is an easy fix.
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:thumbsup: duly noted.

Its strange manufactures dont make a conduit body with the raintight fittings incorporated, or a male RMC connector.
 
Resurrecting a couple of week old thread, question: what size conduit and how is it mounted to the wall?

Small conduit mounted on strut might be far enough away from the wall that a standard radius bend would clear the corner.

This looks like it would work for 1/2 and 3/4" EMT, and _might_ work for 1" EMT if the mount to the strut stands the conduit off slightly, or if the wall corner has a small radius.

Of course this won't work for conduit flush mounted to the wall.

-Jon
 
Smart $ said:
TTBOMK [metal] connectors are not listed for use with any threaded entry or fitting. They are only investigated for grounding continuity using locknuts.
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And yet this, "Internal threads on hubs comply with NEMArequirements. Hubs accept all threadedfittings and threaded conduit." is the wording from Hubbell Raco catalogue regarding Bell boxes, so I think people here sometimes make a mountain out of a molehill. The instruction card on a Bell box tels you to use thread compound or teflon tape on the threads for a wet location. At some point we just need to install things and get the electricity flowing.
 
Strathead said:
And yet this, "Internal threads on hubs comply with NEMArequirements. Hubs accept all threadedfittings and threaded conduit." is the wording from Hubbell Raco catalogue regarding Bell boxes, so I think people here sometimes make a mountain out of a molehill. The instruction card on a Bell box tels you to use thread compound or teflon tape on the threads for a wet location. At some point we just need to install things and get the electricity flowing.
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So you've never run across false statements or statements that stretch the truth on sales literature?
 
Smart $ said:
So you've never run across false statements or statements that stretch the truth on sales literature?
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what I have run across is thousands, or at least over 1,000 connectors screwed in to bell boxes and LB's in the field in my career. I have done it myself, I don't know how many time and I haven't lost one night's sleep over it. I don't think and inspector in the Country would think twice about it unless they read right here on this site that they should be concerned. I am a lot more concerned about the crappy workmanship that I see all the time.
 
Strathead said:
what I have run across is thousands, or at least over 1,000 connectors screwed in to bell boxes and LB's in the field in my career. I have done it myself, I don't know how many time and I haven't lost one night's sleep over it. I don't think and inspector in the Country would think twice about it unless they read right here on this site that they should be concerned. I am a lot more concerned about the crappy workmanship that I see all the time.
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Well by all means, we have to put dealing with crappy workmanship ahead of poor workmanship without fail. ;)
 
Strathead said:
I see you put the wink there, but still imply that screwing a connector in to a bell box or LB is poor workmanship. I call foul.
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For those that don't know it is an issue with the listing of locknut connectors is why they say builds upon ignorance is bliss as being accurate in many cases. For those that do know yet support and continue to do it.... :(
 
Smart $ said:
For those that don't know it is an issue with the listing of locknut connectors is why they say builds upon ignorance is bliss as being accurate in many cases. For those that do know yet support and continue to do it.... :(
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The listing standard does not require that male connectors be tested for connection to female threads. That stops well short of saying you can't do that. I don't see a real world issue and well over 95% of the LMFC connectors I have installed have been used with female threads.
Here is what the White Book says in "Conduit Fittings (DWTT)
All male threaded fittings and nipples have only been investigated for use with locknuts. Fittings with internal female threads (e.g., hubs, conduit bodies, couplings) have only been investigated for use with threaded rigid conduit.
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If you take those words as written, it means that there are no conduit bodies suitable for use with IMC!
 
Smart $ said:
For those that don't know it is an issue with the listing of locknut connectors is why they say builds upon ignorance is bliss as being accurate in many cases. For those that do know yet support and continue to do it.... :(
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I think this is a ridiculous argument and I wish that I got to bid against you if you take this type of position on every single nuance of electricity, because I don't know how you would get anything done. 314.15 merely states that conduit fittings must be listed for use in wet locations. It doesn't say that the entire assembly must be listed together. It doesn't say the have to be listed as an assembly. Red Dot says to ensure a tight seal for threads use Red Dot sealant. Bell boxes have an instruction to use teflon tape or sealant with fittings. All of this imples that using male threaded components in the female threads on the box is a standard acceptable method of attachment. Duct seal at the thread location would prevent intrusion. Entering from the bottom would prevent intrusion.

Given that there are millions of bell boxes installed with various threaded connectors in them, installed for decades and the code council has not decided in all those years to firmly FORBID this heinous violation of good workmanship, is enough anecdotal evidence to me that you may just be overreacting to a situation.
 
IMHO this is not a ridiculous argument, but it may require significant testing to actually settle it.

The issue is that we have an installation practice that is used by many, that seems to work, but which has not been 'vetted' by the testing authorities.

Standard EMT fittings have straight threads that are designed to go into a box of some sort and be held by a locknut.

Standard RMC fittings have tapered threads that are designed to mate with the tapered thread of the conduit.

They both have the same thread per inch values and have similar diameters. So you can screw an EMT fitting into an RMC fitting and it seems to work just fine.

It simply has not been properly tested. Perhaps it works just fine mechanically but would not work properly in fault conditions. Perhaps this doesn't matter if you have a wire EGC along with the conduit. Perhaps perhaps perhaps...

http://www.ecmag.com/section/codes-standards/fittings-hubs

Back to the OP: a standard raintight fitting going into a small NEMA 3 box would seem to be an approach that would be code kosher and provide the small radius.

Perhaps someone could suggest to Arlington that they make 'raintight emt hubs' for their 'anybody' series of conduit bodies. http://www.aimedia.co/media/spec-sheets/ANYBODY.pdf

-Jon
 
Given that many installations make use of straight threaded components going into tapered components (eg. going from flex to rigid) perhaps they should be tested as a common (mis)use.

-Jon
 
Strathead said:
I see you put the wink there, but still imply that screwing a connector in to a bell box or LB is poor workmanship. I call foul.
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The listing issue is about maintaining grounding integrity. i.e. continuity, not water intrusion prevention.
 
Smart $ said:
The listing issue is about maintaining grounding integrity. i.e. continuity, not water intrusion prevention.
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The listing says that reducing washers maintain that grounding integrity, so there is no way that any threaded connection will not be able to do the same.
 
don_resqcapt19 said:
The listing says that reducing washers maintain that grounding integrity, so there is no way that any threaded connection will not be able to do the same.
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The problem is you are saying any threaded connection. Perhaps. But all threaded entries have not been investigated. Reducing washers use the locknut. Some bell boxes have threaded entries, but not full depth hubs; the end of the connector protrudes into the box when the connector is wrench tight, leaving enough connector threads for the locknut to be installed.
 
MAC702 said:
Then if we run a wire EGC, we can do anything we want?
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No... there's this thing about grounding continuity required... :slaphead:

Running a wire-type EGC just makes requirements more complex, not more relaxed.
 
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Smart $ said:
The problem is you are saying any threaded connection. Perhaps. But all threaded entries have not been investigated. Reducing washers use the locknut. Some bell boxes have threaded entries, but not full depth hubs; the end of the connector protrudes into the box when the connector is wrench tight, leaving enough connector threads for the locknut to be installed.
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True, but let's be honest here. How often is that done?

most of us will admit that we simply install the connector and roll. No?
 
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