can 120 and 277 occupy the same raceway

[chriskellaway]

can 120 and 277 occupy the same raceway in not where does it say in the codebook

 

[augie47]

They can provided all the parameters are in place. See 300.3(C).
Also note 200.(6)(D) & 210.5 (C)

 

[donselec]

Yes, generally all conductors in a raceway have to be rated for the highest voltage.

 

[DARUSA]

As long both insulations are rated for the maximum voltage applied to the cables, in this case 277volt THHN and the most commons insulation are 600 volt rated .