MOTOR TERMINATION BOX WITH NO THREADED CONNECTION

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ADub

Senior Member
Location
Midwest
Occupation
Estimator/Project Manager
Why not bolt a threaded hub with the needed opening right to the peckerhead centered over the ko.


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Smart $

Esteemed Member
Location
Ohio
If you want to be really technical this and the other myers hubs are intended to be used with RMC or IMC (with tapered threads) so putting reducing bushings into it is a listing violation.
I think you best go check the listing of your reducing bushing. Why many call all of them an RE, there are reducing bushings that are listed for RMC/IMC, such as an RB...

http://www.emersonindustrial.com/en...rigid-conduit-imc-reducers/Pages/default.aspx

BTW, they have tapered threads.
 

1964element

Senior Member
Location
Chicago
HI. I have found multiple posts regarding this issue but no clear answers.
I have a larger motor with a motor termination box (peckerhead) that has a 3" opening that is not threaded. I have seen in the past where reducing washers have been used. However, any experienced electrician knows reducing washers are a pain in the butt and come loose. As a matter of fact, that is how I have found the reducing washer method is from servicing motors in the field.

In the picture, you can see that there is minimal space from the opening to the wall of the peckerhead. I want to use a myers hub but fear the spacing to the wall will not allow the lock ring to seat correctly.

What other options are there? They obviously intended for some kind of field connection.

I want to make sure I follow the NEC and use a listed and approved method. I am going to try a myers hub with reducing bushings.

I appreciate any help on this.
Chase nipple,locknut,rigid female x female, over to sealtite or whatever you prefer

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kwired

Electron manager
Location
NE Nebraska
I think you best go check the listing of your reducing bushing. Why many call all of them an RE, there are reducing bushings that are listed for RMC/IMC, such as an RB...

http://www.emersonindustrial.com/en...rigid-conduit-imc-reducers/Pages/default.aspx

BTW, they have tapered threads.

I get same ones you linked to from my supplier - I see it does say they are tapered thread yet I haven't yet seen one that won't spin all the way through a rigid coupling - so much for the tapered part I guess:?
 

Smart $

Esteemed Member
Location
Ohio
I get same ones you linked to from my supplier - I see it does say they are tapered thread yet I haven't yet seen one that won't spin all the way through a rigid coupling - so much for the tapered part I guess:?
The large end of the tapered threads is still smaller than the straight threads of a coupling. RB's are intended for hub-type entries of enclosures, conduits bodies, and such.... not couplings, which the use in is technically a listing violation.
 

kwired

Electron manager
Location
NE Nebraska
The large end of the tapered threads is still smaller than the straight threads of a coupling. RB's are intended for hub-type entries of enclosures, conduits bodies, and such.... not couplings, which the use in is technically a listing violation.
You have to do better then that to convince me they are tapered enough to be worth mentioning the taper.

Thread them into a tapered hole or thread a tapered piece into them and of course it will eventually tighten up.
 

Smart $

Esteemed Member
Location
Ohio
You have to do better then that to convince me they are tapered enough to be worth mentioning the taper.

Thread them into a tapered hole or thread a tapered piece into them and of course it will eventually tighten up.
I'm not trying to convince you of anything. It is what it is.
 
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