Threaded RMC into 2 gang w/p box

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StevenL1983

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Louisiana
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Electrician
Does installing threaded RMC wrench tight into the threaded female hub of a 2 gang weatherproof box meet the requirements for a wet location? I’ve got an inspector saying it need a Myers hub and is wanting documentation stating that out installation is ok.
Thanks
 

Dennis Alwon

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Chapel Hill, NC
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If it is a threaded opening then the inspector is incorrect. Is the thread on top or bottom. I'll assume top but that should not make a difference. Put some silicone around the outside and see if that will make him happy.
 

StevenL1983

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Location
Louisiana
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Electrician
It’s on the side. It’s a 5 hole 1/2” KO box. It’s mounted is a manner that there are two holes on the right side and two on the left.
 

Dennis Alwon

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Rmc is rated wet location, the box is rated wet location so I am not sure what he wants. If push came to shove you could use a wp locknut on the outside and thread into the box.
 

infinity

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New Jersey
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Journeyman Electrician
The Myers hub has straight threads designed for use with a locknut if anything using one of those would be a violation.
 

Dennis Alwon

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And with the ko's on the side what is this inspector worried about. We generally use silicone on all threads just for extra security
 

StevenL1983

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Location
Louisiana
Occupation
Electrician
The Myers hub has straight threads designed for use with a locknut if anything using one of those would be a violation.
I know right? It’s a third party inspector on a data center site. They have to try to justify their paycheck. They throw a lot of you know what against the way and hope something sticks. It’s very frustrating
 

roger

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Fl
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I’ve got an inspector saying it need a Myers hub and is wanting documentation stating that out installation is ok.
Thanks
He may be masquerading as an inspector but he's clueless.

Roger
 

Strathead

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Location
Ocala, Florida, USA
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Electrician/Estimator/Project Manager/Superintendent
If it is a Bell box, the instructions say the threads must be sealed, that means either Teflon tape or pipe dope at the time of installation IMO, not silicone around the fitting afterward. Not sure about an FS box.
 

wwhitney

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Berkeley, CA
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Retired
If you're sealing the threads on a metal conduit it needs to be done in a way that does not impede the grounding continuity of the raceway.
But if the threaded connection is made up wrench tight, is it possible to interfere with the grounding continuity? E.g. if you put silicone in the threads before tightening, won't the wrench tight connection involve interference/deformation of the threads, resulting in metal to metal contact?

Cheers, Wayne
 

petersonra

Senior Member
Location
Northern illinois
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engineer
But if the threaded connection is made up wrench tight, is it possible to interfere with the grounding continuity? E.g. if you put silicone in the threads before tightening, won't the wrench tight connection involve interference/deformation of the threads, resulting in metal to metal contact?

Cheers, Wayne
one would think so, but the code seems to think otherwise.
 

Strathead

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Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
If you're sealing the threads on a metal conduit it needs to be done in a way that does not impede the grounding continuity of the raceway.
I guess then that a green grounding conductor would be required, but what does that have to do with the fact that every Bell Box carries that instruction and that makes it a requirement to follow?
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
one would think so, but the code seems to think otherwise.
Citation?

When bonding threaded pressure pipe with joints made with dope, it is assumed that the joint will provide electrical continuity, so there is no need to jumper each fitting. Of course, the standard for bonding conduit may be higher than bonding other systems.

Cheers, Wayne
 
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