Antenna Installation Questions

[fields2004]

I need some assistance on understanding the code.
Here is the situation:
The local power company owns the electricity meter in the house and it contains an internal automatic meter reading transmitter. The transmitter's performance is not adequate so the power company has a contractor that wants to install a small whip antenna on the outside of the house about 6 to 8 feet above ground level.

The coax from the whip antenna would be routed down the exterior wall almost to the earth, then along the side of the house, then penetrate the wall and enter the basement. The coax would then be routed to the electric meter that is mounted in the basement. The coax would then connect to a "flexible strip" antenna that sticks to the outside of the electricity meter's glass or plastic cover. There is an antenna inside the meter, probably 1/2 inch away from the stick-on antenna that is outside of the meter cover. So there is no physical or electrical contact between the meter's internal antenna and the exterior stick-on antenna. Also, there is no DC or AC power on either of the stick-on antenna, coax, or external whip antenna. This arrangement only serves to pickup RF energy transmitted by the meter and couple it outside to a higher antenna to gain more range or better operation.

So the questions are:
1) What Article(s) and subparts of NEC governs the installation?
2) What certifications and/or licenses would the installation contractor typically need to be legally capable of installing the equipment?
3) Are there other standards or regulations that would govern this installation and if so what are they?
4) What clearances, grounding, and bonding requirements govern this installation?

Thanks for your help.

 

[hurk27]

Re: Antenna Installation Questions

Article 800 in general and 800.40 for grounding requirements.

With that said some wouldn't think an isolated lead-in coax shield would require lightning protection connection, But it does.
Being that it might be electrically isolated looking at it from a DC or even 60hz stand point, one might want to think that lightning will just strike something that has a better connection to Earth. This is not true in any sense.
Think of this lightning has no problem striking an aircraft at 20,000 feet in the air, so it would be prudent to realize that it can strike this whip and run in on the lead-in coax jumping to any path it finds "INSIDE" the building. Not a good thing to have.
Lightning is a high frequency event and does not follow the fundamentals that low frequency or DC current does. So Having the shortest path to Earth at or before the point of entrance of this cable (or any phone or cable that enters a building) is a must and a NEC requirement. And it should be done at a point that is close to the service grounding electrode as this is the best connection point to use. The NEC Say's less then 20' from it or another electrode has to be installed and then a #6 grounding electrode bonding jumper has to be ran between each and all electrodes.

If you want to do some reading about lightning protection go "HERE"

Edited to add that utility company's are not required to follow the NEC in almost all locations, they follow what is called the NESC. Just a FYI

[ December 08, 2005, 12:04 AM: Message edited by: hurk27 ]

 

[fields2004]

Re: Antenna Installation Questions

Wayne,

Thanks for the reply. May I probe a bit further?

One goal of my post was to be sure that NEC governs this installation even though there are no energized conductors involved. Based on your response, NEC (Article 800) does govern.

I looked at Article 800, let me see if I interpret it correctly.
For the installation in my first post, if the vertical run of the grounding conductor from the antenna toward earth is within linear 20 feet of the service entrance ground then connect it to the service entrance ground rod. If greater than 20 linear feet then drive a new 8 foot ground rod, connect that rod directly to the antenna grounding conductor, and also bond the new ground rod to the service entrance ground rod with #6 (minimum) conductor.

Now, assume the antenna ground conductor will be connected to the service entrance ground rod. Would it violate NEC (possibly 800.52) to route the ground wire and coax together and secure them both with the same wire clamps.

Often, such an installation will route the coax behind a down pipe of the gutter system such that the antenna can mount on the side of the building that provides the best RF coverage. So, are there clearances (physical) that must be maintained between the antenna, or coax, or ground conductors and the downspout or other plumbing? I assume 800.52 define the spacing between coax and conductors (60 Hz, alarm, telco, CATV, etc.) in the basement?

Part of my first post questioned the licensing of the installation contractor. I know the utility is governed by the NESC but I thought the demarcation point was the lower jaws in the meter socket. Therefore, the NEC would govern everything on the ?customer?s? side of the meter. Is this correct? If so, then whether or not the installer is a utility employee or independent contractor he would be required to install the antenna and other items per NEC regulations and carry some certification? Perhaps a low-voltage license is adequate?

Now let me add a little twist to the situation. A different house and everything is identical to the first situation except instead of the stick-on antenna being attached to the electric meter it attaches to the plastic index (dials) cover on a gas meter. I assume everything discussed still applies?

Thanks for your patience and sharing your knowledge on all these questions.

 

[hurk27]

Re: Antenna Installation Questions

One goal of my post was to be sure that NEC governs this installation even though there are no energized conductors involved. Based on your response, NEC (Article 800) does govern.

I think it would depend upon the AHJ's interpreting of 90.2(B)(5)(a).

a. Consist of service drops or service laterals, and associated metering , or

equipment to enhance the ability to read a meter from the road is still part of the meter equipment?


If the buildings electrode system is farther than the allowed 20' then 800.40(B)(2)(2) only requires a 5' rod or pipe electrode to be installed but it still has to be bonded to the grounding electrode for the service to the building by a wire no smaller than #6 as per 800.40(D)

Again this is only if it even falls under the NEC.