Industrial transformers

[Charm]

In an industrial setting with multiple 480v D-Y 208v transformers and panels.(each
one has a name MB1, MB2, MB3,?) I found a 1900 box with wires terminated from two
different panels say MB2 and MB6 the only labeling the cover says MB4 ckt 33,
35. My question is can you have multiple transformers/panels terminated in one
electric box in this case a 1900 box, or is someone being lazy. If not is there
a NEC reference.
Thank You

 

[infinity]

There is no NEC requirement to keep these circuits separate unless you have something from Article 700.

 

[Pierre C Belarge]

Take a look at 300.3(C)(1) - (2014 NEC)