Is there anything in the NEC that would prevent me from attaching MC cable with ground to EMT with a compression coupling? I will be skinning the MC cable roughly about 10 to 15 feet where it enters a 1900 box to feed an outlet.

Edit: the compression coupling would not be accessible.


The only thing I could think of that might be wrong with that is the wires in the MC may not be listed / marked as THHN or THWN, even though that's what it is.

Could you use greenfield (FMC) and pull in your wire?

Regarding the coupling - I think you'll have to use a MC/AC box connector and EMT box connector joined together by a female-female threaded coupler.

edit: Actually it looks like there are EMT to FMC couplers:


EMT to FMC coupler

  • I also wonder if the compression fitting is listed to be used with MC cable and EMT... – ThreePhaseEel Dec 3 '15 at 0:26
  • Whoa, hold on! I think you'll have to use a barrel - female to female threaded coupler - between an MC box connector and EMT box connector. An EMT connector will NOT work properly nor be listed for use with flex / MC / AC. – batsplatsterson Dec 3 '15 at 0:30
  • Alright, I think I'll use flex with a male threaded connector with THHN and a 1/2" female threaded EMT connector. Skipping the MC and compression coupling all together. – Kris Dec 3 '15 at 2:50
  • Interesting. I am wondering where you found a female threaded EMT connector. We just use a rigid coupling to join two different raceways. They make adapters for just this occasion though. – ArchonOSX Dec 3 '15 at 8:03
  • @ArchonOSX Haha, you're right I need to use a rigid threaded female coupling – Kris Dec 3 '15 at 21:15

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