Facilities that dont mix systems?

[tortuga]

Greetings all
Do any of work on or design facilities that dont mix say 480/277 & 208/120 or 480 and 240/120 or 600/347 systems in the same raceways?
And require all the 480-600V raceways to be identified?
The NEC allows it. Is there a 70E reason some places are not doing it anymore?
Thanks in advance
and happy new year

 

[David Castor]

We generally never put 120 V and 480 V circuits in the same conduit, except for one or two special situations. This was covered in our electrical specifications as well.

AFAIK, there is nothing in NFPA 70E that disallows the practice as long as you meet NEC requirements for insulation ratings.

 

[petersonra]

There is no good reason for it. I don't know why people do it but it's pretty common, either through practice or specification.

It might have something to do with the idea that a lot of the 120 volt circuits might be control circuits and as class 1 circuits maybe they should be separate.

 

[tortuga]

Thanks for the replies,
Apparently there is some sort of '250 volt max limit' for certain technicians / mechanics and they work there for 40 years I am only there for a few weeks.