800.47A Suitable Barrier?

[Zamalik7]

I have an existing site where there is a 480V power cable run in the same conduit at communications cables from one building to another. This is considered and undergroudn feeder. The 480V cable has no ground and needs to be replaced. There are no spare conduits to pull a new cable in and all cables run through "Comm" vaults to another building. This is the only path between the two buildings.

1) 800.47A states that conductors shall be in a section separated by means of brick, concrete, or tile partitions "or by means of a suitable barrier". If I replace the 480V cable with an interlocked armored cable is that a "suitable barrier"? Is there any way to pull a new 480V cable in an existing comm. conduit? I do not believe that the comm cables are rated for 600V.

2) Do I need a ground (I have no neutral)?

 

[hbiss]

If I replace the 480V cable with an interlocked armored cable is that a "suitable barrier"?

IMO yes because it turns the conduit into a chase. Any splices or terminations in the vaults would have to be made in a separate enclosure within the vault or the cable run through without interruption. The cable must extend out of any LV enclosure at the ends of the conduit run and terminate elsewhere as usual per Chapter 3. The armor would need to be grounded.

-Hal