Critical, Life safety, Equipment, and normal.
Remember FEEDERS not branch circuits.
Rubber covered MC Cable???? .Single phase 2 hots , neutal, ground.

Yoop, Code quiz?

Not sure what your asking.

Question is. Is there any problem using rubber covered MC for hospital feeders??

I see nothing to prevent it.
Appears that the critical items come in to play at the branch ckt level.

From past experience, as a helper at the time. If I can recall correctly you need the 2 hour burn on all critical feeders.Which seems to me in a hospital all patient care areas. I remember using M.I cable for this a few tears back. I'd have to check my code book for the article numbers, thisis just off the top of my head. Also seems to me most hospitals I've done work in have panels dedicated to critical loads, usually having generator back up.

Yer thinking of Fire Pumps . Hospital feeders two hr fire rateing I don't think so.

In Ma. We have the 2 hr rateing for feedrs.
However, Some inspectors have trouble diferentiating feedrs from branch ckts.

Doesn't Ma. use only the NEC?? I carried a Ma. License for yrs and took the test (Masters) in 1999 . I don't remember any additions to the NEC at that time.