EMT as a EGC when connected to AL boxes ?

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Stevenfyeager

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United States, Indiana
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electrical contractor
In a barn house, for looks, I want to use aluminum outside weatherproof boxes. Will EMT still work for a EGC ? The threaded EMT fitting screws into the threads of the aluminum box, so there is no room for a nut. This may not be a good grounding connection ? ?
 
While typically not looked at, the UL Guide for EMT fittings (FKAV) says:
Male fittings not provided with a locknut, intended for securement to a threaded hub, are marked on the smallest unit shipping carton, "For securement to a threaded hub only," or the equivalent.

Male fittings provided with a locknut, also intended for securement to boxes with threaded entries, hubs or fittings with internal female threads (e.g., conduit bodies, couplings), are marked on the smallest unit shipping carton, "For securement to a threaded hub," or the equivalent.
Click to expand...
I have never need a connector box marked with those words.
 
Stevenfyeager said:
In a barn house, for looks, I want to use aluminum outside weatherproof boxes. Will EMT still work for a EGC ? The threaded EMT fitting screws into the threads of the aluminum box, so there is no room for a nut. This may not be a good grounding connection ? ?
Click to expand...
Most female threaded products are only rated for connecting to RMC and IMC, and possibly PVC male adapters, which all have tapered threads. It is most common that the only thing that straight male connectors (EMT, LFMC, etc) are rated to thread into, are locknuts and bushings. I agree with Don, that I've never seen one marked with those words, so this could be a hypothetical product standard that has yet to materialize.

The proper way to do this, is to use an RMC close nipple, and an RMC to EMT transition coupling (analogous to a female adapter). Bridgeport has these in sizes up to 1". Not sure what you are expected to do beyond that.
www.bptfittings.com

Bridgeport

BETTER WAYS TO GET THE JOB DONE RESOURCES Related products Bridgeport Compliance Documents ASK US ABOUT BRIDGEPORT
www.bptfittings.com www.bptfittings.com
 
Carultch said:
The proper way to do this, is to use an RMC close nipple, and an RMC to EMT transition coupling (analogous to a female adapter). Bridgeport has these in sizes up to 1". Not sure what you are expected to do beyond that.
www.bptfittings.com

Bridgeport

BETTER WAYS TO GET THE JOB DONE RESOURCES Related products Bridgeport Compliance Documents ASK US ABOUT BRIDGEPORT
www.bptfittings.com www.bptfittings.com
Click to expand...

OZ-Gedney has RMC to EMT couplings up to 2 inch:

https://www.gordonelectricsupply.com/p/Oz-G-Etr-200-2In-Rig-Emt-Comp-Cplg/5917224
 
I'd go with Wiremold boxes w/ 1/2" KO's if they're still available. Use an offset bender for uniform neatness. The boxes are paintable, standard plates are a perfect fit and none of those bell box outrigger fasteners in sight.
 
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