A/A Fuel GTX
Senior Member
- Location
- WI & AZ
- Occupation
- Electrician
When entering a Nema3 enclosure from the top, is a sealing locknut equally as good as a meyers hub for keeping things dry?
When entering a Nema3 enclosure from the top, is a sealing locknut equally as good as a meyers hub for keeping things dry?
Myers hubs are not listed to be used with emt. The threads are not tapered on emt fittings the same as rigid conduit.
I am an engineer, not an electrician and I would like to know the answer to this as well. We often specify grounding bushings on our conduit ends and I understand you cannot install a grounding bushing on a Myers hub.
I am an engineer, not an electrician and I would like to know the answer to this as well. We often specify grounding bushings on our conduit ends and I understand you cannot install a grounding bushing on a Myers hub.
An eletrician we worked with told us that Myers hubs are the only acceptable water-tight fitting. I would appreciate it if someone could confirm this.
Thanks.
Without a seal between the fitting and the top of a cabinet I do not see how an "O" ring on a locknut will seal? water will still go through the threads, Arlington Industries does have UL listed sealing washers that work for PVC male adapters, not sure about EMT fittings.
For installations, I will use sealing locknuts inside for wet or dirty enviroment. Outside I would be more likely to use a meyers, esp on the top.
Hurk, it sounds like the Arlingtons' product contradicts your first sentance. I am using PVC so it sounds like a Meyers Hub and a Male Adapter is out because of the thread difference. The sealing locknut seems like a good choice. BTW, if the sealing lock nut is tight, I don't see how water could get past it. I just want to be sure it is legal........
The answer depends on what type of raceway is intended to be installed into the fitting. I'll explain. Myers hubs are not listed to be used with emt. The threads are not tapered on emt fittings the same as rigid conduit. So in that regard, Yes.
I'll leave it to the others to answer the real question you are asking...
Without a seal between the fitting and the top of a cabinet I do not see how an "O" ring on a locknut will seal? water will still go through the threads, Arlington Industries does have UL listed sealing washers that work for PVC male adapters, not sure about EMT fittings.
Excerpt from UL: DWTT.GuideInfo, Conduit FittingsHurk, it sounds like the Arlingtons' product contradicts your first sentance. I am using PVC so it sounds like a Meyers Hub and a Male Adapter is out because of the thread difference. The sealing locknut seems like a good choice. BTW, if the sealing lock nut is tight, I don't see how water could get past it. I just want to be sure it is legal........
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.
Do you know if PVC fittings are listed?
Excerpt from UL: DWTT.GuideInfo, Conduit Fittings
PVC fittings are not listed to use with a Meyers hub.