Multiple Services, Mixing Circuits

[hbendillo]

I have a hospital facility that has three services. The newest service at a patient tower was done according to currrent codes. Generator, three branches, everything separated and fed according to code requirements. 480-volt, three-phase, 2000 amps. The other two services consist of one transfer switch each and branch circuits and feeders not seperated according to branch or use downstream of the transfer switch. Both of these are 208-volt, three-phase. One is 2000 amps I think and the other 4000 amps. The 4000 amp service feeds a significant part of the existing hospital including the emergency department and radiology. Because of the increasing demand for radiology and mechanical systems loads we recently installed a separate 1600-amp 480-volt service to handle the demand. Well, now every time the owner adds large loads anywhere on the site he wants them fed at 480-volts. This includes the part of the building and service that has no 480-volt component. What are the rules for feeding equipment in one part of the facility, with it's own service, from another part of the building with it's own service. Besides not being good engineering practice in my opinion, what does the code say about it? Oh, he does this with both emergency and normal power loads.

 

[iwire]

Assuming all rules have been followed as to marking and proper separation of the different branches I see no NEC problem at all.

Not even sure I would call it 'bad design'.

 

[rikthejman]

Yes, identify your wiring and circuitry. Just finished a large call center with 240/120 with install of 208/120 3phase with an emergency backup generator etc... Had to put plaques on all the service locations and equipment. Wiring was a nightmare because old wiring was a hodgepodge of colors so ended up with numbering system and schedules at the panels. Good luck.