Question about proper grounding of antenna - AVS Forum
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post #1 of 13 Old 05-06-2012, 05:33 PM - Thread Starter
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Hi all,

I just installed an antenna for OTA reception on an old Dish Network mast from a previous tenant. The mast is attached to a steel clothesline pole, and didn't seem to have any additional grounding.

Is the steel clothesline pole enough of a ground itself that I shouldn't worry? Does the coax cable leading into the house need to be grounded as well?

Thanks for the help...
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post #2 of 13 Old 05-06-2012, 07:00 PM
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Quote:
Originally Posted by atarinox View Post

Hi all,

I just installed an antenna for OTA reception on an old Dish Network mast from a previous tenant. The mast is attached to a steel clothesline pole, and didn't seem to have any additional grounding.

Is the steel clothesline pole enough of a ground itself that I shouldn't worry? Does the coax cable leading into the house need to be grounded as well?

Thanks for the help...

I would ground the coax just prior to it entering the house if I were you. Be safe...not sorry.

~All truth goes through three phases. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as self-evident. - Arthur Schopenhauer ~
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post #3 of 13 Old 05-06-2012, 10:59 PM
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Both the mast and the cable need to be grounded. The odds are that the metal pole isn't an adequate ground if for no other reason than it probably isn't bonded to the electrical system's grounding electrode. An there are other reasons why it probably isn't an adequate ground. And as previously mentioned, the cable shield needs to be grounded where it enters the house, preferably close to the electrical service entrance.
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post #4 of 13 Old 05-07-2012, 06:24 PM
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Quote:
Originally Posted by Colm View Post

Both the mast and the cable need to be grounded. The odds are that the metal pole isn't an adequate ground if for no other reason than it probably isn't bonded to the electrical system's grounding electrode. An there are other reasons why it probably isn't an adequate ground. And as previously mentioned, the cable shield needs to be grounded where it enters the house, preferably close to the electrical service entrance.

CATV does not have to be grounded per se, it has to be bonded to the electrical system properly per code for potential differences. The Actual cable plant does need to be gounded before and after every active and EOL's, plus bonded to electric and telephone where needed.

All Comments made are my own and not of my employer.
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post #5 of 13 Old 05-08-2012, 01:59 PM
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Originally Posted by ybsane View Post

CATV does not have to be grounded per se...

NEC 810.15 Grounding: Mast and metal structures supporting antennas shall be grounded...
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post #6 of 13 Old 05-08-2012, 02:32 PM
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"shall be grounded" It doesn't say they have to use the same ground. There should only be 1 ground for things enetering the house.
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post #7 of 13 Old 05-08-2012, 03:53 PM
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Quote:
Originally Posted by Colm View Post

NEC 810.15 Grounding: Mast and metal structures supporting antennas shall be grounded...

Don't quote the code unless you understand it...

When an electrode such as a ground rod is installed to ground the mast or lead-in cable, it must be bonded with a 6 AWG copper conductor to the grounding electrode system at the building or structure served [810.21(J)].

You cannot use a metal rod driven into the earth for grounding of the lead-in cable, unless the metal rod is bonded with a 6 AWG conductor to the building grounding electrode system in accordance with 810.21(J). In addition, the NEC does not allow you to use the local water pipe [810.21(F)(1)(b)

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post #8 of 13 Old 05-08-2012, 05:02 PM
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Quote:
Originally Posted by atarinox View Post

Hi all,

I just installed an antenna for OTA reception on an old Dish Network mast from a previous tenant. The mast is attached to a steel clothesline pole, and didn't seem to have any additional grounding.

Is the steel clothesline pole enough of a ground itself that I shouldn't worry? Does the coax cable leading into the house need to be grounded as well? ...

Both should be grounded. If the ground is different than the home's main electrical ground, the separate grounds must be bonded together, per posts above.
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post #9 of 13 Old 05-08-2012, 07:15 PM
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Quote:
Originally Posted by ybsane View Post

Don't quote the code unless you understand it...

I understand the code well enough. I suspect you may not understand it as well as you think, though, based on your response to my post. Maybe you ought to follow your own advice.
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post #10 of 13 Old 05-09-2012, 01:11 PM
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In addition, the NEC does not allow you to use the local water pipe [810.21(F)(1)(b)

NEC 2008 [810.21(F)(2)(2) states "The grounded metal interior water piping systems, within 1.52 m (5') from its point of entrance to the building, as covered in 250.52"

Which version of NEC are you using as a reference (in case I need to upgrade...)?


Quote:


CATV does not have to be grounded per se

Grounding requirements for CATV systems are covered in Section 820. In general, Section 820 also applies to the coaxial cable used in most private antenna systems.

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post #11 of 13 Old 05-09-2012, 01:15 PM
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Quote:
Originally Posted by Bob7145 View Post

"shall be grounded" It doesn't say they have to use the same ground. There should only be 1 ground for things enetering the house.


The quotation given was too short. The rest of it states " in accordance with 810.21" which gets more specific and includes the reference to bonding if separate ground electrodes are used. Bonding the electrodes makes them the "same ground".

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post #12 of 13 Old 05-09-2012, 01:47 PM
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Quote:
Originally Posted by ADTech View Post

NEC 2008 [810.21(F)(2)(2) states "The grounded metal interior water piping systems, within 1.52 m (5') from its point of entrance to the building, as covered in 250.52"

Which version of NEC are you using as a reference (in case I need to upgrade...)?




Grounding requirements for CATV systems are covered in Section 820. In general, Section 820 also applies to the coaxial cable used in most private antenna systems.

Your quoting 2008 and need to upgrade, we always try to be current for all our installers/service techs to be as correct as possible. Too much liability these days.

All Comments made are my own and not of my employer.
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post #13 of 13 Old 05-09-2012, 05:56 PM
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Technically, the most recent revision does not become local "code" until a year or two after its cover date. It only becomes the current code after the legislature or appropriate governing body adopts it.
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