Is there any specs/code for the distance/spacing of an electrical conduit and voice/data conduit. This is for a trench between 2 buildings, there will be one conduit for the electrical and one conduit for the copper voice/fiber data cables. Is there a recommended distance to have the electrical conduit from the voice/data to avoid interference? Thanks

Ed or Hal will probably know if there are any NEC specs. When I worked construction for the Bell System our cable direct buried (without conduit) was 12 inches above the power, with a warning tape about 4 inches below our cable, this was for safety reasons.

No. The NEC doesn't have anything to say about it. I always kick one to one side of the trench and the other to the other side. 18 or 24" wide bucket on the backhoe.

-Hal

In my Bell experience, the tel and TV were down about 2 feet, and the primary and secondaries were down at least three feet. That meant that to work on the "less dangerous" wires, you didn't have to move the EL wires out of the way. That was the theory, but in practice, sometimes they got wound around each other.

I have repaired many automatic gates in the estate section of my area, where there was interference between the 110 VAC wiring to the gate motors; and the 6-pair BSW that connected the house, and the telephone system, to the gate squawk box. If the two wires were buried in close proximity, the pulse from the hydraulic pump gate motors would be induced into the telephone/control wires, causing the gate motors to reset and/or do something weird. The effect was gates that acted like they had a mind of their own, opening and closing randomly.

Once I figured it out, of course, it was an obvious fix. Now when I am working with the gate guys and electricians on a new job, I tell them to bury the two wires in separate trenches, or at least a foot apart in the same trench.

Be sure to check local regulations. I've ran into a few odd ones.