480 and 24 vdc in same conduit

[realolman]

Art 300.3 (C)(1) says conductors of circuits rated 600 volts or less can occupy the same raceway if the insulation rating is equal to the maximum circuit voltage rating, regardless of whether they are AC or DC

Art725.26 (B)(1) says Class 1 circuits and power supply conductors can only occupy the same raceway if the equipment powered is functionally related.


1. What does "power supply " conductors mean? Are conductors supplying motors "power supply " conductors? Art725.26(B)(1)

2. Can I install conductors from a 24vdc 10 a. power supply in the same conduit as 480 v motor circuit conductors even if they are not functionally related? Art 300.3 (C)(1)

 

[Pierre C Belarge]

It depends on the supply source.

If the supply source is a Class 2 or Class 3 source, you are not permitted to install the conductors in the same raceway regardless of the insulation.

To discern if the source is a Class 2 or Class 3, those supplies are required to be listed and labeled...you can see the label on the supply.

See 725.41 ('05), 725.121 ('08)
725.52(B) ('05), 725.130(B) ('08)

 

[don_resqcapt19]

...
2. Can I install conductors from a 24vdc 10 a. power supply in the same conduit as 480 v motor circuit conductors even if they are not functionally related? Art 300.3 (C)(1)

No. The rules in Chapter 7 supplement or modify the rules in Chapters 1 though 4. See 90.3. Unless the 24 volt conductors are part of the 480 volt motor control circuit, they are not permitted in the same raceway with the motor circuit conductors. 725.48(B)(1) in the 2008 code or 725.26(B)(1) in the 05.