Rain tight couplings 3 inch

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wireddd

Member
Does anyone know of a manufacture that makes a 3 inch heavywall
setscrew coupling that is considered water tight for outdoor use?
We have to do a service run that requires the last elbow put on but it can't be threaded into a coupling, or any other suggestions as to how to join two threaded pieces without being able to thread them together in a coupling?
 

wireddd

Member
I can't find anyone who will say that an erickson fitting is listed as raintight
Appleton and Crouse Hinds both make a coupling with grounding straps
under the neoprene boot, but these are listed as explosion proof and are about $550.00 each.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Rigid conduit couplings, standard or 3 piece, are not required to be listed as raintight. I'm not sure about the explosionproof one shown in realolman's post, but expect to pay about $100 for that in 3".
The fact that standard threaded conduit couplings leak more than the old compression EMT couplings makes me say that this whole raintight issue fro EMT fittings is bogus. I have no idea what prompted UL to make this move, but as I said it doesn't hold water for me.
Don
 

realolman

Senior Member
I know this is a stupid question, but that never stopped me before.

There's no way this can be accomplished without some sort of union?

PVC is out?

The price of any union seems to be nuts at that size, if you can get it at all.

I'm just curious as to why there is not some other alternative.

( jacking up the building and sitting it down on your conduit :) )
 

wireddd

Member
Thanks for all the help. The concept of over threading the pipe is good as long as the inspector wouldn't consider this a piece of all thread or think the conduit isn't threaded in all the way and not allow it. All manufactures 3 piece couplings would work except for the listing. Not listed as raintite would not meet the inspection. One would think a threaded union would be just as tight as a standard threaded coupling.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
wireddd,
The concept of over threading the pipe is good as long as the inspector wouldn't consider this a piece of all thread or think the conduit isn't threaded in all the way and not allow it.
It is a code violation. 344.42(B).
Don
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
My last use of a 4 inch rigid bender required threads be cut first, with a straight pipe, before bending, since the threader can't hold bent pipe. A side effect of this operation meant overthreading was the only way to achieve the shortest spec. 90's.

A few inches of this warped / threaded end had to be cut off before installation, but almost always resulted in visible threads, of the non-tapered variety, being visible beyond the coupling; technical code violations on several levels, but a necessary evil that informed AHJ's have understood and approved.

Don't AHJ's regularly approve this STD operating procedure for industrial applications. It seemed when studying for my 1999 NEC Cert., just like politician's diplomatic immunity, the NEC makes exceptions to just about every rule for industrial property.
 

don_resqcapt19

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Location
Illinois
Occupation
retired electrician
Roger,
Don't AHJ's regularly approve this STD operating procedure for industrial applications.
Not that I know of.
the NEC makes exceptions to just about every rule for industrial property.[/uote]
The code does not have an exception to this rule. The long threads make a very weak point in the conduit as a result of the depth of the threads. In normal installation the coupling is tightned up onto the taper of the thread, increasing the strength of the pipe and making the grounding connection. When the threads are cut long, the coupling remains on the deep cut threads and the strength is less and the grounding connection poor.
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
don_resqcapt19 said:
Roger,
The code does not have an exception to this rule. ..When the threads are cut long, the coupling remains on the deep cut threads and the strength is less and the grounding connection poor.
I did'nt realize that. Perhaps my lack of seeing this violation enforced is mere coincidence.

However, on a different thread: http://www.mikeholt.com/codeForum/viewtopic.php?p=1182421#1182421
I tried to make the case, with my read of other industrial exceptions that riddle the NEC, it seems factories can just about be burning to the ground as long as its supervised.
 

thinfool

Senior Member
Location
Kentucky
Maybe I missed something, but from what I gather of this question...I would consider a "split coupling". Similar to an OZ SSP-300. :!:
 

tonyi

Senior Member
This needed to be a raintight application. The OZ part is slick, but doesn't look like it could ever be raintight.
 
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