electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Penetrating the top of a outdoor NEMA 3R Gutter/Through?
- Thread starter klaatu
- Start date
- Status
- Location
- Illinois
- Occupation
- retired electrician
The only way that actually works, is just not coming into the top of any enclosure in a wet location.
We're all fortunate to be able to do what we do.
Some of us just have the added luxury of having to pull out a vise, threader, oiler, rigid bender etc... every day.
JAP>
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Why? Neither one is about quality. Sometimes we install the wrong things because 'grandpa' taught us that and we are not about to admit he was wrong.
The NEC says the inside of conduits will accumulate moisture and so it must be arranged to drain, ideally this draining occurs before the conduit enters an enclosure. A Type 3R enclosure is not rain tight not waterproof, it is intended and tested to prevent water from entering above the energized parts.
Sealing locknuts are listed for use with RGS, may be due to the sharp cut threads biting into the elastomeric material versus the more rounded threads of standard EMT connector. Listed RT EMT fittings are also rated to prevent water entering around the threads.
kwired
Electron manager
- Location
- NE Nebraska
I pretty much refuse to use rain tight EMT connectors with the gaskets that come with them, most of them anyway. Seen too many deteriorate within only a year or so and gasket is completely gone after that time, leaving a pretty loose connection that leaks more than if you had used a set screw connector and had an otherwise properly tightened locknut on it. Plus bonding can be compromised when it is loose like that.
I will use a myers hub in top of enclosures when exiting with EMT, and a RT connector threaded into hub, even though technically that combination is not listed, is still better than the RT connector alone. Whoever thought those should be listed needs to be shot.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
The compromise is a close or short nipple and a female adapter.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Well there should be a minimum amount of quality such that something works as intended. UL's standard for RT fittings is apparently junk, and thus the fittings are junk and don't work. Why does it exist then? They aren't just junk, but as Kwired said they are in fact far worse than just using a regular fitting as the gasket will probably be destroyed in a few years (if not destroyed from the assembly process). You can't tighten these things much so mechanical strength and bonding is compromised. Crap, junk, stupid, dumb, balderdash, blistering blue barnacles, crap junk. And the NFPA came up with the requirement and UL allows the junk crap to be made.
Exactly.
Why can't they just design threads on a RT connector that would be compatible with a Meyers hub or any hub for that matter?
Jap>.
And that's because one is trying to use something that it wasn't designed to do.
Why not just accept the facts and require the installations to be rain resistant instead of rain tight?
Jap>
With the integral O ring on a Meyers hub I wouldn't be relying on it too much for bonding either.
Jap
Power Company's overhead drops most generally attach to Service Masts.
Most Service Masts are required to be Rigid conduit.
Rigid conduit is compatible with most hubs unlike EMT Compression or RT connectors.
Thus our dilemma.
JAP>
- Location
- Illinois
- Occupation
- retired electrician
You sure about that?
I've been told most aren't approved grounding and bonding if they don't have the grounding screw accessory.
May have been misinformed.
JAP>
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Is tightening the locknut sufficiently to get a good bonding connection compatible with not overcompressing the o-ring so that it squeezes out and fails? Is there a torque spec for the locknut on a RT EMT connector?
Cheers, Wayne
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Obviously the best design is something like an O-ring boss hydraulic fitting, where there is a machined groove for O-ring that allows it to be compressed to to the proper value with no possibility of destroying it, and the locknut to be thoroughly tightened. The RT EMT connectors with the rubber ring are completely worthless as you can hardly tighten the lock nut at all before it is excessively distorted. Typically this happens before the locknut teeth have even chewed thru the paint. The ones with the plastic ring are a little better, but still pretty much worthless. I cant remember if myers hubs have the machined recess. ITs been a while since I have used one but I dont recall having to be delicate when tightening the locknut.
- Status