Wire Voltage Rating

[Control]

When inter-connecting two control panels of different systems and different feed voltages is it required that the wire in both panels be of the higher panel voltage rating or just the wire that is used in the inter-connection?

Example: Cabinet_1 is 480VAC fed and required to have all internal wiring rated at 600V. Cabinet_2 is 120VAC fed and only required to have all internal wiring rated at 300V. A conduit is run between the two for PLC I/O interconnection with 24VDC in/out. This wire is required to be 600VAC because it enters the 480VAC enclosure but does the fact that it also enters the 120VAC enclosure make the entire enclosure subject to being exposed to 600VAC and thus require all wiring to be 600VAC?

 

[physis]

300.3(C)(1).

This says it's based on actual voltage, not insulation ratings.

But there are other sections I haven't been able to find right now.

 

[augie47]

It is important to address Art 725 also. 725.48(B)(1) for instance limits sharing raceways, 725.26 prohibits sharing raceways.

 

[physis]

I don't have 2008 Gus.



Edit: Oops, I see you got that one too, but:

725.26 Conductors of Different Circuits in the Same Cable, Cable Tray, Enclosure, or Raceway. Class 1 circuits shall be permitted to be installed with other circuits as specified in 725.26(A) and 725.26(B).

 

[physis]

I'll just start over, my editing time expired, here's what I meant to say. Disregard the preivious post.

I don't have 2008 Gus.

There's also 725.26.

Edit: Oops, I see you got that one too, but:

725.26 Conductors of Different Circuits in the Same Cable, Cable Tray, Enclosure, or Raceway. Class 1 circuits shall be permitted to be installed with other circuits as specified in 725.26(A) and 725.26(B).

 

[dbaird]

 

[physis]

This doesn't apply to wiring methods. It applies to equipment constructruction.

 

[jim dungar]

When inter-connecting two control panels of different systems and different feed voltages is it required that the wire in both panels be of the higher panel voltage rating or just the wire that is used in the inter-connection?

The cable insulation needs to be rated only for the voltage to which it may be exposed.

All conductors entering or internal to Cabinet #1 must be rated for 480V (600V per your spec).

All conductors in Cabinet #2 must be rated for the maximum voltage on any of the conductors entering or internal to the cabinet. The fact that a conductor may have been exposed to a higher voltage somewhere else is not important.

 

[augie47]

I'll just start over, my editing time expired, here's what I meant to say. Disregard the preivious post.

I don't have 2008 Gus.

There's also 725.26.

Edit: Oops, I see you got that one too, but:

725.26 Conductors of Different Circuits in the Same Cable, Cable Tray, Enclosure, or Raceway. Class 1 circuits shall be permitted to be installed with other circuits as specified in 725.26(A) and 725.26(B).

I think it'd just a relocation...thats similiar to the same wording as -08 725.48
(1) In a Cable, Enclosure, or Raceway. Class 1 circuits and power-supply circuits shall be permitted to occupy the same cable, enclosure, or raceway only where the equipment powered is functionally associated.