MOTOR TERMINATION BOX WITH NO THREADED CONNECTION

[riverjig87]

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.

 

[Cow]

I too have seen MANY loose reducing washers. Myers hubs/reducing bushings are KING. Even if the environment doesn't call for a good waterproof connection, I still use them.

 

[Aleman]

Yes reducing washers are about useless. I have seen motors like this and never have figured out why the holes are so damn big.
One method we have tried is to flip the peckerhead and drill a proper sized hole. Then use what you want and plug the original hole
with regular hole plug.

 

[ADub]

Bolt a 4" square blank to it with the right size entry punched in it.


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[sii]

Seconding the Meyers hub method.

 

[Smart $]

... I want to use a myers hub but fear the spacing to the wall will not allow the lock ring to seat correctly.
....
I appreciate any help on this.

With the limited clearance I recommend using what I call a female hub. That's not what it is actually called so it took a little digging to find it. Crouse-Hinds calls it a "conduit hub - iron space-saver". See the second page of the following pdf...

http://www.cooperindustries.com/con...ercial-products/catalog-pdfs/conduit-hubs.pdf

 

[iwire]

Bolt a 4" square blank to it with the right size entry punched in it.


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Likely what I would do.

 

[1964element]

Trim the Meyers lock ring with a bandsaw

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[Strathead]

With the limited clearance I recommend using what I call a female hub. That's not what it is actually called so it took a little digging to find it. Crouse-Hinds calls it a "conduit hub - iron space-saver". See the second page of the following pdf...

http://www.cooperindustries.com/con...ercial-products/catalog-pdfs/conduit-hubs.pdf

Things like this are exactly why I frequent Holt and read trade magazines. I don't do field work any more, but I always catalog things in my brain to use later on. I just bought an offset mudring for a job where they were putting in a new wall. No one else had ever heard of one, and I had never ordered one, because I never needed one. I will put this in the vault and one day find a use for it for sure.

 

[kwired]

With the limited clearance I recommend using what I call a female hub. That's not what it is actually called so it took a little digging to find it. Crouse-Hinds calls it a "conduit hub - iron space-saver". See the second page of the following pdf...

http://www.cooperindustries.com/con...ercial-products/catalog-pdfs/conduit-hubs.pdf

Other then it is a malleable iron hub I don't see any difference from what others call a Myers hub which are usually die cast zinc.

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.

 

[iwire]

Other then it is a malleable iron hub I don't see any difference from what others call a Myers hub which are usually die cast zinc.

I am a bit confused as well.


This item is what I will receive if I ask for a Myers hub and like you I don't see an obvious difference other than cast vs malleable. :huh:

 

[Strathead]

It looks to me that the outside diameter of the Crouse Hinds is quite a bit smaller relatively compared to the outside ridge of the Meyers Hub locknut. Perhaps my perspective is wrong.

 

[infinity]

I think that Smart is recommending that product when there is limited clearance since it smaller than a Myers hub. We typically use reducing washers with a bonding bushing.

Does anyone know why the KO's in peckerheads ares so big? You would think that the average electrician has an easy way to enlarge the hole if needed. :rant:

 

[iwire]

It seems much bigger.

 

[infinity]

It seems much bigger.

Scroll down. It's on page 2 of the pdf.

 

[iwire]

Scroll down. It's on page 2 of the pdf.

DOH! :ashamed1: :dunce:

Well that certainly clears it up, thanks.

 

[kwired]

Does anyone know why the KO's in peckerheads ares so big? You would think that the average electrician has an easy way to enlarge the hole if needed. :rant:

They must think we are going to always use oversized conductors for voltage drop.

When you have dual volt motors and are running the higher voltage I have had cases of 3 inch KO size in the motor and had to reduce to as little as a 1 inch supply raceway. I'd really prefer they let us make our own hole or at least a small hole and let us enlarge it if needed.

 

[infinity]

They must think we are going to always use oversized conductors for voltage drop.

When you have dual volt motors and are running the higher voltage I have had cases of 3 inch KO size in the motor and had to reduce to as little as a 1 inch supply raceway. I'd really prefer they let us make our own hole or at least a small hole and let us enlarge it if needed.

When going to connect the motor for me the likelihood of having a KO set is much greater than having an odd sized set of reducing washers like 1.5"-3/4".

 

[Fulthrotl]

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, to a 3" GRC coupling. then a sealtight fitting into that.
gives you a bit of wiggle room in the coupling for wire scooching.

assuming you aren't feeding it with 3", then a RE in the coupling.
if you use a long chase nipple, it should fill up the coupling to
halfway, and the RE will fill most of the rest of it.

 

[kwired]

chase nipple, to a 3" GRC coupling. then a sealtight fitting into that.
gives you a bit of wiggle room in the coupling for wire scooching.

assuming you aren't feeding it with 3", then a RE in the coupling.
if you use a long chase nipple, it should fill up the coupling to
halfway, and the RE will fill most of the rest of it.

Reducer and coupling both will have non tapered threads - so will never tighten, just bottom out.