Not sure?

[Robert "Butch" Smith]

Does the NEC allow us to run a 120 volt circuit in the same conduit as a 3 phase 480 volt circuit?

 

[charlie b]

Yes, if the wires all have insulation that is good enough for at least 480 volts. But since most wire has 600 volt insulation, that should be easy to meet. Reference 300.3(C)(1). Be aware of the derating requirements for having more than three current-carrying conductors in the same conduit. Reference 310.15(B)(3).

Welcome to the forum.

 

[don_resqcapt19]

In general, yes, as Charlie stated, but there can be code compliance issues if the 120 volt conductors are control or signaling conductors and not power conductors.