Erickson couplings and wet/damp locations

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Carultch

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I'm looking at Erickson 3-piece couplings, and I'd like to know whether they are built for wet locations by design by being threaded RMC fittings, or if there is a specific requirement for them to be listed this way, just like there is for threadless fittings.

Few (if any) standard RMC couplings indicate on datasheets that they are for wet locations. I've seen a T&B datasheet that indicates 3-piece couplings are rated raintight, and other manufacturers' datasheets omit this information, yet there doesn't seem to be a clear difference in the construction of the part.

The environment in question is a vertical conduit stub on a rooftop, which has "close quarters" that limit the ability to install anything above it by spinning it. If you do install an Erickson on a piece of vertical conduit, what is the best orientation to arrange to drain?
 
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Carultch said:
I'm looking at Erickson 3-piece couplings, and I'd like to know whether they are built for wet locations by design by being threaded RMC fittings, or if there is a specific requirement for them to be listed this way, just like there is for threadless fittings.

Few (if any) standard RMC couplings indicate on datasheets that they are for wet locations. I've seen a T&B datasheet that indicates 3-piece couplings are rated raintight, and other manufacturers' datasheets omit this information, yet there doesn't seem to be a clear difference in the construction of the part.

The environment in question is a vertical conduit stub on a rooftop, which has "close quarters" that limit the ability to install anything above it by spinning it. If you do install an Erickson on a piece of vertical conduit, what is the best orientation to arrange to drain?
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Standard couplings aren't exactly water tight, the threads are not tapered.

I don't worry about it though, if outside you will get more water inside from condensation then will ever leak past threads.

Same reason I feel the listed "raintight" EMT fittings introduced a few years back that made standard compression fittings no longer acceptable for outdoor applications are a joke.
 
kwired said:
Standard couplings aren't exactly water tight, the threads are not tapered.

I don't worry about it though, if outside you will get more water inside from condensation then will ever leak past threads.

Same reason I feel the listed "raintight" EMT fittings introduced a few years back that made standard compression fittings no longer acceptable for outdoor applications are a joke.
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So in practice, would you install anyone's 3-piece coupling in an outdoor environment, and not be concerned with the raintight issue?

I'm surprised that raintightness isn't part of the default design of RMC parts, since I seldom find an application of RMC that is in a dry location. Maybe parking garages where vehicles can hit conduit on the wall. But mostly RMC is my standard for outdoor use.
 
Carultch said:
So in practice, would you install anyone's 3-piece coupling in an outdoor environment, and not be concerned with the raintight issue?

I'm surprised that raintightness isn't part of the default design of RMC parts, since I seldom find an application of RMC that is in a dry location. Maybe parking garages where vehicles can hit conduit on the wall. But mostly RMC is my standard for outdoor use.
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I've used many of them outside, never was any concern. I expect outdoor RMC to get moisture inside whether it leaks around fittings or not.
I have worked around a lot of grain storage bins - nothing is immune to condensation on those things, better design it to drain, as well as remember to never enter top wall of equipment directly above something you absolutely want to keep dry. If you don't design it to drain and have a "trap" in the conduit, it will fill with water, freeze in the winter and break the pipe open. Seen many that have done exactly that.
 
Carultch said:
So in practice, would you install anyone's 3-piece coupling in an outdoor environment, and not be concerned with the raintight issue?

I'm surprised that raintightness isn't part of the default design of RMC parts, since I seldom find an application of RMC that is in a dry location. Maybe parking garages where vehicles can hit conduit on the wall. But mostly RMC is my standard for outdoor use.
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Everyone's experiences differ. The only raceway we run in our facilities is grc regardless of the environment. I'm also under the impression that there's always a way to spin it together if you want it bad enough and plan accordingly.


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ADub said:
Everyone's experiences differ. The only raceway we run in our facilities is grc regardless of the environment. I'm also under the impression that there's always a way to spin it together if you want it bad enough and plan accordingly.


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There is also no shame in using a three piece coupling to speed things up.
 
iwire said:
There is also no shame in using a three piece coupling to speed things up.
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I agree and I don't like it when they're not used advantageously. I was just saying for the sake of argument that if the op was that worried about the union being watertight he could find a way not to use one


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ADub said:
I'm also under the impression that there's always a way to spin it together if you want it bad enough and plan accordingly.
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iwire said:
There is also no shame in using a three piece coupling to speed things up.
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Back in the days of my apprenticeship, I met a couple ol' timers that would tear a building down before they would use an Erickson.
 
ADub said:
I agree and I don't like it when they're not used advantageously. I was just saying for the sake of argument that if the op was that worried about the union being watertight he could find a way not to use one


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I don't think I could find a way not to use one. I don't think there exist herringbone nipples and couplings, and threadless fittings in this size are not available raintight.

344.42(A) specifies threadless fittings requiring this rating.

Nowhere does the RMC article specify that standard couplings require a raintight rating, and we know that standard couplings don't have it. So by code, where would a 3-piece coupling fall, relative to whether it needs or doesn't need the rating?
 
Carultch said:
I don't think I could find a way not to use one. I don't think there exist herringbone nipples and couplings, and threadless fittings in this size are not available raintight.

344.42(A) specifies threadless fittings requiring this rating.

Nowhere does the RMC article specify that standard couplings require a raintight rating, and we know that standard couplings don't have it. So by code, where would a 3-piece coupling fall, relative to whether it needs or doesn't need the rating?
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As best I can tell, RMC fittings are not required to be rain tight, whether they are used in wet areas or not. they are required to be listed though. As long as they are listed, I think they are fine.

344.10 Uses Permitted.
(A) Atmospheric Conditions and Occupancies.
(1) Galvanized Steel and Stainless Steel RMC. Galvanized
steel and stainless steel RMC shall be permitted under
all atmospheric conditions and occupancies.
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These are the only special requirements for using RMC in wet locations as far as I can tell.
344.10 Uses Permitted.
(D) Wet Locations. All supports, bolts, straps, screws, and
so forth, shall be of corrosion-resistant materials or protected
against corrosion by corrosion-resistant materials.
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Nothing about fittings or couplings having to be anything special in wet locations.
 
petersonra said:
As best I can tell, RMC fittings are not required to be rain tight, whether they are used in wet areas or not. they are required to be listed though. As long as they are listed, I think they are fine.

These are the only special requirements for using RMC in wet locations as far as I can tell.

Nothing about fittings or couplings having to be anything special in wet locations.
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Thanks for the clarification.

Does 314.15 apply to conduit systems in general? Or is that in a section that is specific to junction enclosures and conduit bodies?
 
Carultch said:
Thanks for the clarification.

Does 314.15 apply to conduit systems in general? Or is that in a section that is specific to junction enclosures and conduit bodies?
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It seems clear to me that the scope of the article would not cover conduit fittings being used as conduit fittings only.

314.1 Scope. This article covers the installation and use of
all boxes and conduit bodies used as outlet, device, junction,
or pull boxes, depending on their use, and handhole
enclosures. Cast, sheet metal, nonmetallic, and other boxes
such as FS, FD, and larger boxes are not classified as conduit
bodies. This article also includes installation requirements
for fittings used to join raceways and to connect
raceways and cables to boxes and conduit bodies.
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I often used 3 piece couplings in wet locations, but only for horizontal runs.....the 3 piece coupling leak a lot more than standard couplings in vertical runs so I would use an explosion proof union for vertical applications.

Note, I am not aware of anything that says you can't use 3 piece couplings in wet locations....that was just my practice
 
Carultch said:
Even though it also says:
This article also includes installation requirements
for fittings used to join raceways and to connect
raceways and cables to boxes and conduit bodies.
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Then we have a problem as I have not found a marking or listing that says standard conduit couplings are suitable for use in wet locations.
 
don_resqcapt19 said:
Then we have a problem as I have not found a marking or listing that says standard conduit couplings are suitable for use in wet locations.
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I believe standard couplings are listed by definition/reference in section 344 (2011). If you need a rain-tight 3-piece you can look here.
 
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