grounding an antenna

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  #1  
Old 01-21-13, 12:24 PM
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grounding an antenna

I'm hoping someone can make sure I am thinking correctly. Note that I am a consumer, not an electrician, although I know my way around an electrical panel and have added a sub panel myself.

To ground an outdoor antenna, I should connect it to a ground rod, this is what the manual says for the antenna.

However I've also read that multiple grounds at the home is bad, and what they really mean is to connect it to your home breaker panel ground.

I have an air conditioner that is outdoors used for central air; this unit has a ground.

So, what I was thinking is this:

-I install the antenna, I get myself some 14 ga outdoor UL-listed wire. I take that wire, attach it to my antenna on the one side, then attach the other side of the wire to the ground that is being used for my outdoor air conditioning unit.

Is this safe? or misguided at best?
 
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Old 01-21-13, 01:08 PM
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They probably want you to connect it to a separate ground rod in case lightning hits it.

Mod Note: All grounding systems need to be connected together. A stand-alone rod for the antennae does not meet code.
 

Last edited by pcboss; 01-21-13 at 08:02 PM.
  #3  
Old 01-21-13, 02:02 PM
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the coax and ground would also be near my main water line - i wonder if attaching ground to my main water line would be OK?
 
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Old 01-21-13, 02:16 PM
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one other point I want to emphasize.

My house was built in 1904, so it's old. But, it does have GE circuit breakers in the service panel. It has the typical three poles (2 120v and 1 neutral)

My service panel, as far as I can tell, does *not* have a ground.
 
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Old 01-21-13, 02:17 PM
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Normally, the water pipe is a good ground but there is a chance that lightning can hit the antenna, so I would buy the approved grounding rod.

PS I'm sure the box is grounded somewhere, if not inside, look out side where the meter is.
 
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Old 01-21-13, 02:53 PM
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You haven't mentioned the type of antenna that you are installing and the manufacturer's intent for the installed ground. Is it a safety ground or will it provide a ground plane for the antenna? They are two different animals.

If you are concerned about a safety ground I would not connect to anything that forms part of the house's electrical circuits. Why not just buy a separate ground rod?
 
  #7  
Old 01-21-13, 04:38 PM
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Easy question, lots of potential answers. Here is my direction for a higher than roof line TV antenna on a steel mast or even chimney or roof mounted:

Yes, there should be a close, 8' ground rod driven to handle the potential lightning current. But, that is not enough. You can still sustain plenty of damage with a close strike.
I don't understand your reference to the central air ground; is this a ground rod??

You also should attach the antenna ground rod to the service entrance ground rod, per NEC, using #6 Cu bare or insulated wire. This insures the entire home wiring jumps to the same potential as your TV just did. If your 1904 home has no service entrance ground rod, now is a great time to add one!

The advice on not using multiple grounds is misguided. Lots of grounding electrodes is fine, maybe even better, but they need to be bonded together, again #6 AWG minimum. Metallic water pipes, service entrance/meter pan ground rod, lateral neutral, and UFER conductors are all used per code. You will see reference to 14AWG to be used for some telephone, satellite dish, etc, but it won't carry 98% of lightning hits like 6AWG copper will.
 
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Old 01-21-13, 05:02 PM
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I'd ground the antenna to the intersystem bonding termination

http://www.platt.com/CutSheets/Arlin...5-CutSheet.pdf

You may have to add the grounding bridge as it didn't appear in the code till 2008.
 
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