cell tower dc bonding jumper sizes

[gadfly56]

I would not even take a second glance at the grounding and bonding design for an engineered cell tower. That is a very specific installation and the designers know what is needed to make the system work correctly.
I might look at the service and the normal electrical equipment, but beyond that, I am leaving that all up to the cell company's engineers.

Except in this case, the designer hasn't provided "what is needed to make the system work correctly". He or she left off the size of the conductor. Shall we go with 22 AWG?

 

[don_resqcapt19]

Except in this case, the designer hasn't provided "what is needed to make the system work correctly". He or she left off the size of the conductor. Shall we go with 22 AWG?

If it is on the cell equipment side, I am not going to look at it.

 

[gadfly56]

If it is on the cell equipment side, I am not going to look at it.

Hmmm, so a "Today my jurisdiction ends here," sort of thing?

 

[ActionDave]

Does anyone in your organization actually concern themselves with this ??
I've seen a hundred +- cell towers inspected and the farthest I've ever seen an inspector look was the termination of the feeder.
The site engineers normally verify the grounding.

I've worked on a bunch of cell towers and I've never seen one that didn't have extensive grounding specs written into the design.

 

[LarryFine]

I've wired two cell sites, one on the ground and one atop an apartment building.

My scope of work was A.C. power in and grounding electrode conductors.

My responsibility for grounding stopped at the copper bonding plate.

 

[hhsting]

Well anyways please see the scope of 810:

when it says radio I think not sure it is intended for AM/FM radio or other radio that we listen. Radio that we listen in car.

Unless I am mistaking do you all think that 810 covers cell tower sites antenna and RRHs for mobile use such as AT&T, Tmobile etc grounding and bonding? If not then where is that covered in NEC 2014 to go back to post #1 question of what code section to use conductor size of B1? Please your opinion.

 

[steve66]

Well anyways please see the scope of 810:

when it says radio I think not sure it is intended for AM/FM radio or other radio that we listen. Radio that we listen in car.

Unless I am mistaking do you all think that 810 covers cell tower sites antenna and RRHs for mobile use such as AT&T, Tmobile etc grounding and bonding? If not then where is that covered in NEC 2014 to go back to post #1 question of what code section to use conductor size of B1? Please your opinion.

But what about 90.2(B)(4)? Not covered: Installations of communications equipment under the exclusive control of communications utilities located....

 

[tom baker]

But what about 90.2(B)(4)? Not covered: Installations of communications equipment under the exclusive control of communications utilities located....

Exactly, NEC does not apply. Cell company does towers, its up to them.

 

[Fred B]

Exactly, NEC does not apply. Cell company does towers, its up to them.

At least not on it's own, AT&T design specs specifically mention Article 250 and ANSI code, and NYC code mentions 250, 810 and ANSI code.
My understanding is if another specification source by code or by design brings in by reference a NEC code, that it becomes enforceable even if it otherwise would not be applicable.

 

[steve66]

At least not on it's own, AT&T design specs specifically mention Article 250 and ANSI code, and NYC code mentions 250, 810 and ANSI code.
My understanding is if another specification source by code or by design brings in by reference a NEC code, that it becomes enforceable even if it otherwise would not be applicable.

There is a difference between something being specified by the owner or a client, and what is legally adopted as a code requirement by a jurisdiction.

In the example you have provided, it's the utility referencing certain codes and standards, which IMO takes us back to what Tom said:

Cell company does towers, its up to them.

 

[ceb58]

We always used a #6 from the equipment racks and such to the grounding ring including the grounding shield of the wave guides to the antennas. Your best information on towers like this is Motorola's R-56 guide for tower sites. It has Motorola's guides backed up and for the most part above the NEC.