Clearance: Signal Line and Comm Line

[charlie b]

Please see the attached photo. The red signal head was recently installed under a project I have since inherited. The comm line above it was existing. The first owner complaint was that the wires bump into each other. The contractor (part of the design/build team of which my company is the design arm) suggested installing a "fiberglass guy strain insulator" to keep the two cables separated. We are now being told by the owner that this does not meet clearance requirements. They cited 225.14 and 800.44(A)(4). Power to the signal head is well under 600 volts.

I cannot get this to make sense. For open conductors under 600 volts, 225.14 points to you the clearance requirements of table 230.51C. That table talks about spacing between supports, and then spacing between conductors. We do not have open conductors that are spaced certain distances apart. We have open conductors between two poles that are much farther apart than the distances in that table. So I don't think any part of this applies to my installation.

Next, 800.44(A)(4) speaks of clearances between a communication line entering a building and a power line entering a building, with both originating at the same pole. But we are not dealing with a service to a building, so I don't think that applies.

So what I need to know if whether there is a code section that established a minimum spacing between the two cables in the photo.

 

[charlie b]

I am wondering whether 225.14(C) has my answer, that the circuit feeding the signal head only need be kept 4" away from the "other system" (i.e., the comm cable). Comments?

 

[don_resqcapt19]

I don't see where either of those sections would apply. You don't have "open conductors" so 225.14 does not apply and you don't have service drop or overhead service conductors so 800.44(A)(4) does not apply. I think this is one of those cases where the NEC does not really cover the issue. Maybe there would be something in the NESC.

 

[charlie b]

What you are telling me is that the phrase "open conductors" mean uninsulated, bare metal cables. Is that right?

 

[don_resqcapt19]

What you are telling me is that the phrase "open conductors" mean uninsulated, bare metal cables. Is that right?

Not bare, but my understanding is that open conductors are individual conductors, not cabled conductors.

 

[charlie b]

I don't think the signal head is fed from a three-phase source. But suppose it is a 120 volt, single phase circuit. I believe the hot, neutral, and ground wires are individually insulated, and contained within a common jacket. Would that be enough for me to say that 225.14 does not apply? I don't see the phrase "open conductor" defined anywhere, but that article clearly only applies to open conductors.

 

[don_resqcapt19]

I see this much like 230.9(A). We don't need to keep service entrance cable from windows. We must keep open conductors and cabled conductors without an overall jacket 3' from windows.

 

[hurk27]

Up charge them to install taller poles or new poles so that the two can be separated more, from the photo I can see the support wire for the light is drooping down to the point that both the light and support wire can rub the cable at least from the photo view, I could see where this can be a concern if the area gets allot of wind, but I don't see how you could get any more tension to pull it up as those small poles would not take it, but point out that it does meet the code as far as what they claimed that doesn't apply? so if they want more clearance then it should be an upcharge?

 

[tom baker]

Who owns the comm line? If a utility then they don't fall under the NEC