article 404.8b Voltage between adjacent devices

[jdou]

I am currently redoing the hibay lighting in my companys' shop. They have had outside contractors in to build new offices, walls, remodeling etc. When I was recruited to do this-ha- I did a little research as to how the shop lighting was laid out, and found the existing 277v hibay lighting on 2 circuits, a phase and b phase, and on 2 switches within the same switchbox. As it stands, it seems that there is 480v between the 2 devices in this switchbox, which is a code violation per 404.8b. The "powers at be" that I must deal with argue that the devices are considered "individually" and do not exceed 300v.
If the switches were on the same phase,but still separate circuits, would this still be a violation as the voltage between the 2 devices would be 0?
Thanks

 

[iwire]

As it stands it is a violation.

If you make each of the circuits on the same phase it will meet code.

You can also get a barrier for many boxes that will meet code.

 

[480sparky]

Then you have 480 volts between adjacent devices. The NEC pretty much makes it clear what to do.

If they're on the same phase, then you would have 0 volts between them, and no barriers are needed. But my guess is they need to be on separate phases because it's a MWBC.

 

[jdou]

re: adjacent devices

re: adjacent devices

thought so- thanks, jeff