4th Wire (neutral) on a 480/277V, 3phase

[clsarmiento]

A Furnace requires 277V, 1phase for its heating elements (277V, 1phase, 19.5KW per circuit). 480V, 3-phase, 3-wire power is brought in to a fused disconnect switch via 3/C, MC cable. Can a 4th wire be brought in to the neutral terminal block at the switch to get the 277V required? Thanks for help!

 

[jumper]

I doubt it 330.3(B). Your install does not seem to fit any (B)(1)-(B)(4).

(B) Conductors of the Same Circuit. All conductors of
the same circuit and, where used, the grounded conductor
and all equipment grounding conductors and bonding conductors
shall be contained within the same raceway, auxiliary
gutter, cable tray, cablebus assembly, trench, cable, or
cord, unless otherwise permitted in accordance with
300.3(B)(1) through (B)(4).