Proper coupler from 1/2" EMT to 3/8" FMC?

[don_resqcapt19]

The paper that @infinity links is spot on about why it is plausible that such home made transition fittings might not work properly...buy I'd lay money (not much ) on my claim in post #10. Rephrased: 'They probably work just fine but have not been evaluated to demonstrate that they work just fine.'

My guess is that an officially evaluated component to allow home made transition fittings would have something that looks like a conduit coupling, but with straight threads, and possibly special locknuts to firmly bind the connector to the coupler.

Maybe there is a market?

That is exactly the case. They have not been evaluated for that purpose.
I don't think any physical changes would be needs to pass the evaluation to use male threaded connectors with conduit couplings or other fittings having female threads.

 

[garbo]

I am guilty of doing this countless times when I didn't have a transition fitting. I never was called on it or realize it wasn't permitted unit i read it on this forum.

We always used a 1/2" chase nipple thru the undersized IEC motor pecker heads to a RMC coupling. These little maybe 2.5 by 2.5" pecker heads with the 6 or 9 studs gave little room. If you used a T & B sealtite fittings on these boxes the end of the fitting came close to studs. Also had the studs short out when only a little water entered enclosure so ended up taking the stud blocks out & wiring nutting 480 volt.