Romex/NM-B through EMT conduit

[javyLSU]

Hello everyone, I'm in the process of installing a dedicated 20A circuit to power a lift in my garage. I will be running 12/2 NM-B from my main panel across the basement ceiling and through a small 12x2 that forms part of the wall between the basement and garage.

My question is this - given that the exposed cable is more "susceptible to damage" in the garage, is it ok to run the NM through surface-mounted EMT conduit for the last 10 feet of the run to the receptacle, or should I splice in THHN for the last 10 feet? Thanks for any help you can provide!

 

[benjamintmiller]

Yes, you can run NM-B through EMT, so long as the you do not exceed 53% of the cross-sectional area of the conduit. For NM, the area of the conductor is a circle with diameter equal to the wide dimension of the cable.

When I did this last for 12/2, it was able to be pulled through 1/2" EMT.

This being said, it is usually considered poor form to run NM-B through EMT for more than a few feet. Your application of just the last few feet is probably the only application most electricians would approve of. It is common in unfinished basements to run NM in the joist bays, then drop down in EMT to a receptacle.

 

[benjamintmiller]

I forgot to add, you will need a bushing at the start of the EMT run. Here's a good thread with more info:

https://forums.mikeholt.com/showthread.php?t=97639

 

[javyLSU]

Thanks so much for the help @benjamintmiller

 

[alfredeneuman]

Yes, you can run NM-B through EMT, so long as the you do not exceed 53% of the cross-sectional area of the conduit.

That rule only applies to EMT from end to end, and doesn't apply to sections used for protection.

 

[SarcasticDwarf]

That rule only applies to EMT from end to end, and doesn't apply to sections used for protection.

alfredeneuman is correct. You will need the following:
- Bushing at the end (hint: The split ones ****, get the single piece bushings)
- Proper attachment of the box and support for the EMT.
- Proper grounding for the metal box (you will need a pigtail)

 

[javyLSU]

Thanks again for the great advice!