Attic Installation of Antenna - AVS Forum
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post #1 of 9 Old 02-11-2007, 07:52 AM - Thread Starter
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Does an attic mounted antenna need to be grounded? Does it matter if the coax lead is completely in-wall or if part of the lead is outside?
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post #2 of 9 Old 02-11-2007, 08:04 AM
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All antennas probably should be grounded.

A Boy Scout here in Utah was killed last year when lightning hit him while in bed in a wooden cabin. The experts explained that, in most homes, the electrical wiring, and other metal "stuff", in the attic usually acts as a cage over the rest of the house, catching any lightning that might want to land on your particular patch of the earth. The Scout Cabin had no wiring, plumbing, or air conditioning to distract the lightning from coming all the way inside.

Most of your electrical wiring terminates at your breaker panel, where things are well grounded. Without a ground on the antenna, any surges will have to go through your TV and sound system, to get to that same ground.

If the wiring goes outdoors (down an outer wall) anyway, a ground block (with a proper ground wire back to the electric meter or breaker box) would be easy to install. You might want to check with the local building inspector's office, or an electrician, for the full-skivvy on local codes.

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post #3 of 9 Old 02-11-2007, 01:45 PM
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IMO, it certainly does not hurt to ground an attic antenna, but I have a non-grounded one and research convinces me I have nothing to worry about. As pointed out elsewhere on this board, the real danger is static buildup caused by winds and there's little wind in the attic. And I just can't see lightning sometimes penetrating a roof and striking an antenna -- or even striking or being conducted through an outside portion of lead-in. Also, I have no doubt damage would be awful in some bizarre case of a strike, ground or no ground.

The last I checked, NEC code doesn't require it -- even for that outside portion -- and I've never heard of any local codes doing so either.

This is just one non-expert view! Others?
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post #4 of 9 Old 02-12-2007, 06:20 AM
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My only experience with an attic antenna was a 4228 hanging upside down from the highest point of the roof. The hot water heater was also in the attic (in SC), so I grounded the antenna to the copper cold water line. I figured that was sufficient insurance for a fairly unlikely event, and took all of ten minutes to do.

Anything worth doing, is worth doing to excess.
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post #5 of 9 Old 02-12-2007, 06:44 AM
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Not a good grounding practice. Earth ground, when using a cold water line should be terminated at the entry point of the home (usually before the meter).
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post #6 of 9 Old 02-12-2007, 08:19 AM
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I agree with "ratman"....just because you have copper water pipes inside your house, they could connect to a non-metalic pipe where it enters the home. Many water companies and builders no longer run metalic pipe from the house to the meter at the water main. This means you do not really have a buried "earthed" ground on the copper pipes at all.
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post #7 of 9 Old 02-12-2007, 08:37 AM
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Not only that, but the fact is that IF your antenna has a lightning strike, the ground will follow the path of least resistance. So, the intent is to get the discharge to "earth" as close/soon as possible as opposed to allowing the discharge to run through the entire water system.
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post #8 of 9 Old 02-12-2007, 09:41 PM
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Tjhe cold water line was grounded in the crawl space at the point where it joined the incoming non-copper feed from the street. It may have been builder overkill, but there it was.

Anything worth doing, is worth doing to excess.
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post #9 of 9 Old 02-13-2007, 09:27 AM
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If it's a "non-metallic" feed from the street, then those "grounds" are doing absolutely nothing.
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