MWBC

[wwhitney]

The only requirement for for a non-metallic wiring method is that the ends of multiple cables or raceways used for a single circuit comply with 300.20.

That also applies to wiring methods with a nonmagnetic sheath. Presumably that covers aluminum clad multiconductor MC cable and aluminum EMT. But then does the NEC require you to use nonmagnetic fittings? Or are most fittings zinc or pot-metal, so they would be nonmagnetic anyway?

Cheers, Wayne

 

[don_resqcapt19]

That also applies to wiring methods with a nonmagnetic sheath. Presumably that covers aluminum clad multiconductor MC cable and aluminum EMT. But then does the NEC require you to use nonmagnetic fittings? Or are most fittings zinc or pot-metal, so they would be nonmagnetic anyway?

Cheers, Wayne

I think that issue is covered by 300.20. However, it is not a real world issue until the current exceeds 200 to 300 amps, and even then there might not be enough heat at a wiring method termination to be an issue.

 

[Knuckle Dragger]

If you were running several 20A MWBC(s) using 12-3, and you ran out of 12-3, and completed the install using (2) 12-2, would you tie both neutrals together or cap one off?
Seems if you tie them together you would be creating a parallel circuit and the #12 is too small for that.

FYI: There is a reason to keep the MWBC and not change to individual circuits.

I would not connect one of the white wires and cap off at both ends and label what you have done. in the switch box to help avoid confusion for you or the next guy.