ebservicesllc
New member
On a NEMA 3R disconnect with concentric knock-outs; is it required by code to install a Myers hub?
A sealing locknut would be the bare bone minimum I can see using on the side of a 3R box. Assuning a 3R box was used because of environment. Locknuts are not rated for such an environment. A Sealing Locknut is and normally used if coming the side of a box. Myers hubs are great for treaded pipe as long as the top is smooth and no rings. After the choir read in on Meyers hubs back around Halloween....
I think 312.2 and 314.15 will support my position.
I. Installation
312.2 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 (
1⁄4-in.) airspace between the enclosure and the wall
or other supporting surface. Enclosures installed in wet locationslive parts shall use fittings listed for wet locations.
shall be weatherproof. For enclosures in wet locations,
raceways or cables entering above the level of uninsulated
Sealing (Liquid-tight) Locknuts — 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 sealing locknut on the inside 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 and used on the inside of the enclosure.