Required Use of Myer's Type Hubs?

[riggz]

I've been told by the inspector that I must use Myer's type hubs for my service gear. Here is what I currently have:



Basically it's a 200A 480v 3ph panel in a 3R enclosure attaced to a 3R tap box (for the contactors and time clock) and to the meter base. I was under the impression that if you made entry into a 3R enclosure below the level of termination blocks, you were not required to use a Myer's hub. I have used sealing lock rings going to the panel enclosure with PVC T/A's. The pipe is 3" PVC.

I understand that it's the authority having jurisdiction's final interpretation of the code, but I haven't been able to locate what part of the code governs this. My on site personnel didn't bother to ask what article of the NEC he was calling this from.

Any input is greatly appreciated!

 

[jwelectric]

312.2 Damp, Wet, or Hazardous (Classified) Locations.
(A) Damp and Wet Locations. In damp or wet locations, surface-type enclosures within the scope of this article shall be placed or equipped so as to prevent moisture or water from entering and accumulating within the cabinet or cutout box, and shall be mounted so there is at least 6-mm (?-in.) airspace between the enclosure and the wall or other supporting surface. Enclosures installed in wet locations shall be weatherproof. For enclosures in wet locations, raceways or cables entering above the level of uninsulated live parts shall use fittings listed for wet locations.

 

[tshea]

I believe you have complied by using sealing locknuts!

Ask the inspector what's the reference.

312.2 Damp, Wet, or Hazardous (Classified) Locations. For enclosures in wet locations, raceways or cables entering above the level of uninsulated live parts shall use fittings listed for wet locations.

 

[iwire]

For enclosures in wet locations, raceways or cables entering above the level of uninsulated live parts shall use fittings listed for wet locations.

Along with Mike's reference I will point out sealing locknuts can meet this requirement.

 

[buck33k]

I am under the impression that sealing locknuts are listed for use with threaded rigid metal conduit and intermediate metal conduit only. Maybe someone can help me with a reference.

Carlon does make an o-ring (E943W) to be used with a PVC terminal adaptor, but it is not UL listed and to be honest, I do'nt know if it has to be.

It seems like the sealing locknut or o-ring in this case would work well if the inspector would accept it.

Buck

 

[infinity]

I am under the impression that sealing locknuts are listed for use with threaded rigid metal conduit and intermediate metal conduit only. Maybe someone can help me with a reference.

Carlon does make an o-ring (E943W) to be used with a PVC terminal adaptor, but it is not UL listed and to be honest, I do'nt know if it has to be.

It seems like the sealing locknut or o-ring in this case would work well if the inspector would accept it.

Buck

When you buy a terminal adapter does it come with a locknut? No, you buy the same locknut that you would buy for rigid conduit. I don't see where a sealing locknut would need to be listed for a terminal adapter. But I have been wrong in the past.

 

[-marty]

On this install we would only be required to use meyer's hubs if a conduit entered the top of an enclosure.

If the raceway was emt we would use the rain-tite connectors instead of a meyer's.

 

[don_resqcapt19]

If the enclosure is a 3R, and you are using the factory KOs, you don't need a hub or sealing locknuts. 3R enclosures are not intended to be watertight...only to keep the water off of the energized parts. If you look, you will see that all 3R enclosures have drain holes in the bottom.
Don

 

[ARBY]

From the UL White Book: Sealing locknuts are intended for use with threaded rigid metal conduit and intermediate metal conduit with one sealing locknut in the outside or the inside and either an ordinary locknut or a sealing locknut on the opposite side of the enclosure for wet locations or liquid-tight applications. Sealing locknuts may also be used with Listed wet location or liquid-tight fittings where so marked on the fitting carton.

 

[riggz]

so i guess i will have to discuss this with the inspector on his next visit to the job site. i don't see how a myers hub is any more water resistant than a sealing locknut other than it has an O-ring on the actual T/A. thank you all who contributed! way more responses than i expected for my first post here.