Myers hub?
The OP was an academic question. I wasnt sure what the code section would be.
While we are at it, lets summarize. I see 4 ways to enter the top of a 3r cabinet:
1. Meyers hub
2. PVC TA with one of those O-rings for the purpose
3. Raintaight EMT connector
4. RGS nipple with sealing washer
5. Liquid tight flexible conduit with proper connector
6. Bolt on hub that is designed to be used with that particular cabinet.
The OP was an academic question. I wasnt sure what the code section would be.
While we are at it, lets summarize. I see 4 ways to enter the top of a 3r cabinet:
1. Meyers hub
2. PVC TA with one of those O-rings for the purpose
3. Raintaight EMT connector
4. RGS nipple with sealing washer
In reality only one of the above actually keeps the water out in my opinion.
The only one that keep the water out is not on the list.
If you want to keep the water out do not enter the top, enter low on the sides or up from underneath.
I have had job specifications that did not allow top entry at all.
In reality only one of the above actually keeps the water out in my opinion.
JAP>
Also however, in most instances, why do we need to keep water/most of the water out at all?
Sometimes water follows conductors from a top entry right to the terminal and causes corrosion at that terminal, or worse yet runs right into a breaker or other device. It don't have to be water that leaked in either, it can just be condensation that formed inside the raceway.That's a good point that most don't ever stop to think about.
Sometimes its more about keeping the bottom of the enclosure from eventually rotting out rather than protecting what's inside of it.
JAP>
Sometimes water follows conductors from a top entry right to the terminal and causes corrosion at that terminal, or worse yet runs right into a breaker or other device. It don't have to be water that leaked in either, it can just be condensation that formed inside the raceway.
Same here. I recently did some work at a place I did new installation back about when the RT EMT fittings first became an issue. Most of the RT fittings either had cracked and pulling away gasket or completely missing gasket and mechanically were loose which also compromises bonding.:roll:For water to follow a conductor inside of a completed raceway that's terminated in the top of an enclosure (Not caused from condensation), the water would first have to leak past the fitting or fittings connecting the raceway to the top of the enclosure.
None of the fittings in post #22 are designed to keep condensation from somehow forming inside of a raceway, but, as far as my choice for a termination fitting that would best keep normal water intrusion out of an enclosure, I'd put my money on the Meyers Hub along with a threaded connection beyond it before any of the other 3.
JAP>