Meyers Hubs needed?

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smooth.eddy

Member
Hi.....I am new here...

Anyway, my question is with Meyers Hubs and Nema 3R and Nema 4 J boxes. I thought that a meyers hub was needed when entering above energized parts with a conduit. But, I have not been able to find the standard in the NEC, American Electrician Handbook or even from Hoffman. I thought it would void UL if regular locknuts were used outside on a 3R or Nema 4 box. Our local inspectors are not enforcing the use of meyers hubs and I think we all know that water will enter when they are not used. I have seen caulk used, but I think this is only a temporary fix.

Any thoughts?

Eddy
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
"Myers hubs" are never required.

Sometimes listed fittings are required which could be sealing locknuts or sealing rings etc.

Check out NEC 312.2(A) last sentence.
 
Rockyd

Rockyd

Senior Member
Location
Nevada
Occupation
Retired after 40 years as an electrician.
Hey Bob (iwire),

Looking for a little further expansion on the verbage of "Fittings listed for wet locations". Short of writing the panel review, and getting a formal interpetation from NFPA, what exactly qualifys per legal definition? Is it what the AHJ makes as the call, per local addendum? Or if it is listed in the scope of work on the prints, does that force the issue?

I've tried to get our client to go for Myers style fittings on top of the box, sealing lock nuts on the sides, and just double locknut on the bottom. They like Meyers all the way around for liabilty (EYD in the box bottom, sometimes on boxes subject to potential standing water in the bottom from "sweating" in classified spaces), is their claim to fame on the issue. I have to offer up a higher standard than "the rest of the world is okay with it" as they are scared to death of a court battle envisioned because someone didn't do the perceived correct installation per NEIS, or whatever they felt was neccesary to keep them protected.

I can understand fear and legalistics, but as long as I do my job to the highest standards (especially when no one is looking) and current "industrial application' to insure a quality job, I stand by my tagline - "Don't let fear be your guide!"
 
S

smooth.eddy

Member
312.(2) A

312.(2) A

After reading 312.2... I don't think this is a requirement for using Meyers Hubs.


I think a rain tight EMT compression fitting fits into this requirement? This is what one of my contractors used in the side of a NEMA 4 box. Then he put silicone around it to make the final seal. It's too bad we don't have a standardized requirement for outdoor work.

Eddy
 
N

nakulak

Senior Member
Carl Ewing said:
Yea, you gotta be fast to beat Bob !
( Of course that's probably why he chose Clint Eastwood for his avatar )

Carl :)
Click to expand...

yeah I just wonder when, exactly, he sleeps ?:grin:
 
E

emahler

Senior Member
nakulak said:
yeah I just wonder when, exactly, he sleeps ?:grin:
Click to expand...

bob doesn't sleep, he naps...and one eye is always open, and one hand is always on the keyboard...he's hardcore:D
 
jrannis

jrannis

Senior Member
Location
Fort Lauderdale/ Miami
Read up on what the manufacture says. I was suprised to learn that sealing locknuts were only tested on rigid conduit. I suppose,for an entry above the equipment or a top penetration, you could use a short nipple and a sealing locknut connected to lets say a PVC female adaptor and be OK.

BTW does your specs call for myers hubs? If not you should be able to get a change order for the extra work.
 
H

HighWirey

Senior Member
Location
Cocoa, Florida, USA
"Read up on what the manufacture says. I was suprised to learn that sealing locknuts were only tested on rigid conduit. I suppose,for an entry above the equipment or a top penetration, you could use a short nipple and a sealing locknut connected to lets say a PVC female adaptor and be OK
BTW does your specs call for myers hubs? If not you should be able to get a change order for the extra work"


A good (organized) competitor recenty won a bid for a potable water plant upgrade in Cocoa, Fl. He interpreted the spec to mean that 'sealing locknuts' were acceptable for bottom entrance into Nema 3,4 panels. He completed the project, then the inspector pulled the spec (and his interpretation) on the EC (how lowbrow of the inspector - reason 101 why to get a good raport with your inspector from the getgo). EC had to change 'em all out. Do you have any idea how many bottom entries there are in a big plant? Neither do I. His project is still in litigation.

Lesson here is: read those specs, ask questions prior to bid time. Even having to eat the myers after bid is better than changing them out after the plant is almost in operation.

This is what memories are made from . . .

Never cared for sealing locknuts, kind'a like eyewash

Best Wishes
 
Rockyd

Rockyd

Senior Member
Location
Nevada
Occupation
Retired after 40 years as an electrician.
I have a copy off the specs for ALL project work to be bid on.

3.3.6 Junction boxes -

The contractor shall intall junction boxes as indicated on the drawings.

1. Conduit connection to sheet metal boxes shall be with a hub properly aligned and tightened to ensure equipment grounding is maintained.

2. Conduit connection to explosion proof boxes with drilled and tapped holes shall be made in accordance with section 9 of UL standard 886.

and it gets a lot worse....

So yes, I install Myers in dumb places. Still try to do the best I can within the given parameters.

When we hear another contractor beat us, we laugh at how much "they forgot". My copy of specs is over 116 pages before going into testing, FCO, etc. So part of the bid is politics and "secret" things that the client wants.
 
H

HighWirey

Senior Member
Location
Cocoa, Florida, USA
rockyd,
"I have a copy off the specs for ALL project work to be bid on"

That was cardinal rule 1 here. Each estimator was required to sit down for an hour or two, whatever it took, to read, heed, and apply the full strength contract docs and the specs to his bid. No exceptions.

You could easily 'buy yourself a project' by overlooking plain English, and those 'weasel worded' clauses.

Happy New Year Everyone and Best Wishes
 
Rockyd

Rockyd

Senior Member
Location
Nevada
Occupation
Retired after 40 years as an electrician.
I'm just a foreman, but I believe good work, will get more good work...on down the line. Not my job to estimate, but it is my job to make my contractor look good, especially when they keep dragging me back to where? And...for how much?
 
jrannis

jrannis

Senior Member
Location
Fort Lauderdale/ Miami
HighWirey said:
"Read up on what the manufacture says. I was suprised to learn that sealing locknuts were only tested on rigid conduit. I suppose,for an entry above the equipment or a top penetration, you could use a short nipple and a sealing locknut connected to lets say a PVC female adaptor and be OK
BTW does your specs call for myers hubs? If not you should be able to get a change order for the extra work"


A good (organized) competitor recenty won a bid for a potable water plant upgrade in Cocoa, Fl. He interpreted the spec to mean that 'sealing locknuts' were acceptable for bottom entrance into Nema 3,4 panels. He completed the project, then the inspector pulled the spec (and his interpretation) on the EC (how lowbrow of the inspector - reason 101 why to get a good raport with your inspector from the getgo). EC had to change 'em all out. Do you have any idea how many bottom entries there are in a big plant? Neither do I. His project is still in litigation.

Lesson here is: read those specs, ask questions prior to bid time. Even having to eat the myers after bid is better than changing them out after the plant is almost in operation.

This is what memories are made from . . .

Never cared for sealing locknuts, kind'a like eyewash

Best Wishes
Click to expand...

Unless the specs called for myers hubs, I would maybe loan the inspector some tools for him to change them.
 
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