I know that plumbing threads are tapered, but not sure electrical PVC is. A lock nut will go all the way up, so I doubt it.

 

Sounds about right, except I think it's the other way around, Male PVC is straight threads and the meter hub is tapered. This is why you will see meter hub=ridgid nipple=female PVC adapter, it's the approved way to transition.

 

Beats me. Never not seen a PVC male adapter used. Same thread as a rigid electrical nipple.

 

The way I remember it, is that plumbing and electrical dies are the same. Tapered thread. But the female threads are different. Electrical is straight, plumbing is tapered.
The other difference is in PVC. Male adapters are straight. That’s why it won’t thread into a hub all the way. Two straight threads. And the hub is meant for tapered threads. It’s probably listed that way. There are many threads on here about it.

 

Maybe that would explain why MAs don't thread all the way into weatherproof boxes. So, if I took an MA & threaded it into a die to make its threads tapered, it should screw in all the way?

 

CEC
12-1112 Fittings

2) Female threaded PVC adapters shall be used together with a metal conduit nipple to terminate at threaded conduit entries in metal enclosures.

 

I don't think it's a tapered thread thing it's a different coefficient of expansion thing.
Which is to say the plastic will expand more bigger than the female metal fitting. This will cause the TA to break. That's why a metal TA works in a pvc FA.

 

I agree, never seen anything other than a PVC MA used at a meter hub, but I have always noticed it doesn't thread in all the way before it bottoms out.

 

 

I hear the USA doesn't have them...

 

MH thread on the subject...

PVC Male Adapter to hub

Hello My inspector informed me that PVC male adapters are not rated to thread into hubs. The print specified PVC mast, where do I find this rating

forums.mikeholt.com

I like the close nipple & FA fix for the problem.