NEMA 3R Enclosure Rigid Conduit Entrance on Side

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akazici

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I have a Nema 3R enclosure with side penetrations I made with rigid galvanized conduit. I used double locknuts. I was thinking if you are not penetrating the enclosure from the top I do not need to use the myer's hub. Any references on this ?

I have checked the NEC 312.2, but I have no live parts in the enclosure it is just a pull box.

Thanks in advane
 
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akazici said:
I have a Nema 3R enclosure with side penetrations I made with rigid galvanized conduit. I used double locknuts. I was thinking if you are not penetrating the enclosure from the top I do not need to use the myer's hub. Any references on this ?

I have checked the NEC 312.2, but I have no live parts in the enclosure it is just a pull box.

Thanks in advane
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WHERE did you penetrate it?

In general penetrations of 3R enclosures (without the benefit of a "waterproof" thing like a hub) are in lower part of the enclosure. If the top of your penetration is above the lowest terminal then you have violated the design. The idea with 3R is that any water that gets in is below any termination, and since the conductors are rated for wet locations, letting them get wet is ok. Sometimes there are holes in the bottom of a 3R to let the water out.
 
Water from wash down or storms is not always the only problem,one other that had to be dealt with in industrial units was condensation forming within the conduit and draining into the enclosure,we would use a a "TEE" fitting with reducer and drain on the lower vertical hub,a short nipple and sealing washer with a lock nut inside on the horizontal hub of the "TEE". The shoulder of the hub on the "TEE" would compress the sealing washer against the enclosure wall as the lock nut was tightened.This approach may get you by the 112.2 requirement as an option.



dick
 
akazici said:
I have a Nema 3R enclosure with side penetrations I made with rigid galvanized conduit. I used double locknuts. I was thinking if you are not penetrating the enclosure from the top I do not need to use the myer's hub. Any references on this ?

I have checked the NEC 312.2, but I have no live parts in the enclosure it is just a pull box.

Thanks in advane
Click to expand...



A pull box would require that all of the conduit entries be listed for wet locations. {314.15}
 
kingpb said:
IMO - I believe the integrity of the NEMA 3R enclosure rating has been compromised based on my understadning of the installation details.
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I realize why you are saying this and also why!

What if the manufacture of a cast device box only has one knock out in the back of box & non threaded.
This box has cast attachment holes.

Now more interesting is where a exterior cast box is used for a GFCI they don't use the tab's supplied (one has to
assemble the tabs), but someone drills holes for set pins instead. There are indents for implied usage of a pin or screw inside the cast.

Does these boxes loose it NEMA rating if one uses these opening(s) and a little silicon?
 
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infinity said:
A pull box would require that all of the conduit entries be listed for wet locations. {314.15}
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I don't understand. It was my understanding that if you have a 3R enclosure with knockouts, that you were allowed to connect non-waterproof box connectors to the locations of the knockouts. You were not allowed to connect non-waterproof box connectors above the knockouts. These knockouts were always placed below the terminals of any equipment in the enclosure.

The theory is that water is allowed to be in the 3R enclosure as long as it doesn't rise to the level of the terminations.

Now if the enclosure is used as junction box, and the splices are above the conduit entrance is this not the same situation?

Some 3R enclosures have opening(s) on the top but these require hubs or filler plates.

So where am I confused?:?
 
If the installation falls under 312.2, like a meter enclosure then only the penetrations above the energized parts are require to be rated for wet locations. If that same installation were a junction or pull box then all the penetrations are required to listed for wet locations. So if you had RMC in the top and out of the bottom the both ends would require Myers hubs or sealing locknuts.
 
infinity said:
If the installation falls under 312.2, like a meter enclosure then only the penetrations above the energized parts are require to be rated for wet locations. If that same installation were a junction or pull box then all the penetrations are required to listed for wet locations. So if you had RMC in the top and out of the bottom the both ends would require Myers hubs or sealing locknuts.
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But why the bottom and only for boxes other than meter enclosures? :? what is the code section?

Water usually doesn't go up.
 
infinity said:
If the installation falls under 312.2, like a meter enclosure then only the penetrations above the energized parts are require to be rated for wet locations. If that same installation were a junction or pull box then all the penetrations are required to listed for wet locations. So if you had RMC in the top and out of the bottom the both ends would require Myers hubs or sealing locknuts.
Click to expand...

I won't disagree with you that what you say is the requirements.

I will say I think a fitting that seals is stupid coming out the bottom of a 3R enclosure. 3R enclosures are supposed to drain, Ther are combination 3R/12 enclosures out there, and to convert from NEMA 12 to 3R all you do is remove some drain plugs or screws from the bottom. If it were a NEMA 12 enclosure then definitely need a seal or you no longer have a NEMA 12 installation.
 
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