Thanks for the great responses as to the oxygen question ! I have talked with the owners of the building ( state of maryland prison system ) , the general contractor, and am awaiting a reply from AHJ, and we are going with the engineers thought and if it needs correcting it will be on his time.
Safetygem - the room is in a new building at a maximum security female prison, it is located off a corridor the seperates medical/dental and security.
As to flex (FMC) into transformers - can't find anything about this in NEC so I'm keeping it the way I feel is best ( AHJ has approved this method )
