Clearances required between 13.2kV open conductor and communications cables

[joshtrevino]

I am working on a project where we are installing a pipe rack under an existing pole line which has 13.2kV open conductor three phase circuit on top and insulated communications cables routed on the poles below the 13.2kV. In order to keep our required clearances between the ground and the 13.2kV, the pipe rack must be installed at the same elevation as the insulated communications cables.

Both the 13.2kV and the communications cables are not utility owned, but are owned by the customer, so I would prefer NEC reference over NESC.

Where are clearance requirements for communications cables found for comm cable to open conductor exceeding 1000V and comm cable to pipe rack?

We would like to move the communications cables up above the rack, but want to ensure we do not infringe on clearance requirements to the 13.2kV open conductor above.

 

[hbiss]

As far as I know the NEC does not cover pole line installations. My advice would be to defer to your utility's specifications.

I can say this- the primary is ALWAYS at the top of the pole with the secondaries and then the communications below. Communications are always at the bottom. As I remember, the communications cables must be at least 40" below the secondaries. Don't remember the clearance from secondaries to the primaries but it has to be something like 96" and dependent on the voltage.

Not sure what you mean by a pipe rack running along the poles. Here in ConEd territory they do use a triplex cable, probably 4160V maybe 13.2Kv to supply substations that power the railroad. That is located above the secondaries.

If you can't maintain specifications you need to replace the poles.

-Hal

 

[Hv&Lv]

I can say this- the primary is ALWAYS at the top of the pole…

-Hal

I wouldn't bet my life on it. Ive worked on systems with neutral on top.

 

[hbiss]

Agreed. That's a shield wire bonded to the neutral. I assume it is supposed to take a lightning hit before anything else.

Help this guy out. What is your spacing on the pole between pri, secondary and communications.

-Hal

 

[don_resqcapt19]

As far as I know the NEC does not cover pole line installations. My advice would be to defer to your utility's specifications.
...

-Hal

Article 225 applies in the 2020 code. In the 2023 code, it would be Article 225 and 235. However, I don't think the NEC gets into the spacing between overhead conductors of various systems. Pretty sure you would have to look to the NESC for those details.

 

[Julius Right]

In my opinion, the last edition of NESC it is 2017.
I have only 2007 edition with me.
Section 22.
Relations between various classes of lines and equipment
220. Relative levels
A. Standardization
Section 23.
Clearances
Table 235-5—
Vertical clearance between conductors at supports

 

[Hv&Lv]

40“ below energized secondary lowest point. Drip loops usually lowest points

 

[ScottWJ]

We would like to move the communications cables up above the rack, but want to ensure we do not infringe on clearance requirements to the 13.2kV open conductor above.

Could you put cable tray on the pipe rack and move the comm cables to the tray?

 

[hbiss]

However, I don't think the NEC gets into the spacing between overhead conductors of various systems.

That's what I was meaning to say.

-Hal