Nec 300.3

[angel woodruff]

300.3 (C)(1)
Conductors of circuits rated 600 volts, nominal, or less, ac circuits, and dc circuits shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway.

If my 480v and 24v are run in separate wire ducts within the enclosure does the 24v wiring need to maintain the same insulation rating as the 480v?
Can I get away with using a 600v rated wire for the 480v and a 300v rated wire for the 24v signals?

 

[lowryder88h]

300.3

300.3

I would agree w/ your assessment as long as it doesn't fall under Art. 725.55 classification separation.

 

[don_resqcapt19]

And even if the signal circuits are Class 1 circuits, and not coverd by 725.55, they can only be in the same raceway as power conductors if they are functionally associated with the power conductors. 725.26(B)(1).
Don

 

[tom baker]

300.3 (C)(1)
If my 480v and 24v are run in separate wire ducts within the enclosure does the 24v wiring need to maintain the same insulation rating as the 480v?
Can I get away with using a 600v rated wire for the 480v and a 300v rated wire for the 24v signals?

What type of enclosure? Is this a control panel? Perhaps UL 508A applies and not the NEC. However the UL50A rules for separation are similar to the NEC.

 

[angel woodruff]

reply

reply

Yes, it is a controls enclosure with a bank of servo drives, control circuits, I/O and safety circuits.