300.3 (c) (1)

[joeyww12000]

I came in on the job Im on late in the process. I noticed all J boxes have been labeled either 120v or 277v. All 120v and 277v have been seperated and run in seperate conduits. While there is nothing wrong and, probably a safer installation method, I asked why it was done this way. I was told you cant run 120/208v with 277/480v. I said 300.3 says you can. After reading it again now Im not sure. The wording states, 2005 NEC, Conductors of circuits rate 600V nominal, or less, ac circuits, and dc circuits, shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. Now it sounds like the distinction is between AC and DC circuits being allowed in the same raceway??

 

[iwire]

The NEC allows mixing 480Y/277 with 208Y/120.

Sometimes specification may prohibit it, or if some conductors are part of the emergency system they have to be separate.

 

[joeyww12000]

I was sure you could, just after rereading I got a little skeptical on whether NEC was talking about mixing voltages 600v or less, or mixing alternating and direct current.

 

[iwire]

Just keep in mind class 2 and 3 wiring as covered in Article 725 has restrictions about mixing those systems with power and lighting conductors.

 

[cowboyjwc]

People always asked me why I did it that way and It was pretty simple, the power was coming from two different places and usually going to two different places. Usually it wasn't going to really save any time running it in the same conduit.

Just remember that you need to identify you conductor colors now as well as your neutrals and carry those colors thourghout the system.

I live right next to your sister city Chatsworth, CA:smile: