Antenna Ground

[lile001]

Sprint has some cell antennas on top of a hospital we are working at. They have a ground wire running down through conduit, to a chemical ground. As far as I can tell it is not bonded to the electrical service. I have to move their wire because it is in the way of some construction, so once I touch it, it has to be put back right. That means a bonding wire to the main service ground or building steel.

Is there any exception to the rule that all ground rods need to be bonded to the main service ground that would apply here? I can just hear them complaining already "no - we need a quiet ground for our antenna .... "

P.S. - they call them "quiet" grounds because the people that get killed when they grab them, and also grab something not bonded to them are very quiet after the initial blood-curdling yell.

 

[raider1]

Is there any exception to the rule that all ground rods need to be bonded to the main service ground that would apply here?

No, 810.21(J) specifically requires that a bonding jumper not smaller than #6 be used to connect the radio/television equipment grounding electrode and the power grounding electrode system at the building where separate electrodes are used.

Chris

 

[steve96a8]

Is #6 awg copper wire sufficient for antenna?

Is #6 awg copper wire sufficient for antenna?

What benefit would there be to using larger wire? #4 or #2
WB3SJU

 

[K8MHZ]

No, 810.21(J) specifically requires that a bonding jumper not smaller than #6 be used to connect the radio/television equipment grounding electrode and the power grounding electrode system at the building where separate electrodes are used.

Chris

If this is a cell site the rules governing telephones are followed here. That does not automatically relieve the requirement for all systems to be bonded.

The cell engineers may not like for their ground drop to be bonded. They may have a waiver from the AHJ allowing them to use their own grounding, isolated from AC mains, under engineering supervision.

I wouldn't touch the antennas without consulting Sprint. If they do let you work on their system, they will need to schedule a possible outage window and be prepared for a re-route in the event of signal failure, which is possible any time you work on a communications system.

Another thing to be wary of.....the grounding electrode conductor may have RF emanating from it, especially if it is open somewhere. If the conductor is cut to just the right length it could become a parasitic element and pose a hazard to personnel and disrupt the coverage pattern of the antenna.

 

[hurk27]

Sprint has some cell antennas on top of a hospital we are working at. They have a ground wire running down through conduit, to a chemical ground. As far as I can tell it is not bonded to the electrical service. I have to move their wire because it is in the way of some construction, so once I touch it, it has to be put back right. That means a bonding wire to the main service ground or building steel.

Is there any exception to the rule that all ground rods need to be bonded to the main service ground that would apply here? I can just hear them complaining already "no - we need a quiet ground for our antenna .... "

P.S. - they call them "quiet" grounds because the people that get killed when they grab them, and also grab something not bonded to them are very quiet after the initial blood-curdling yell.

I would not touch it, this is Sprints property, if they are leasing the space from the owners and you touch it and cause harm to there equipment you can be liable, as far as the bonding to the electrical GE, I would say 90.2(B)(4) might come into play. but Sprint has to be notified no matter what!

 

[dereckbc]

You are between a rock and hard place. I work for Verizon Wireless and design protective ground systems at cell sites. Sprint is in clear violation of NEC and even their own engineering/installation practices.

I agree with Wayne, I wouldn?t touch this with a 10 foot pole. I would get in touch with your client and inform them and let them coordinate with Sprint.