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Old 2012-03-20, 10:27 AM   #841
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Someone suggested using a lightning arrestor instead of a grounding block - anybody know a good place to buy one of these? I couldn't find one at any of the big hardware stores (Rona, Home Depot, etc.) or at The Source...

Edit - I found a combo ground block / arrestor on Amazon today, but apparently I can't put an Amazon URL here (shouldn't I be allowed to do that in the Where to Buy section?). Anyways, it's $13 plus shipping...

Last edited by jmrudow; 2012-03-20 at 03:08 PM. Reason: Attempted to add a link to Amazon...
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Old 2012-03-20, 10:33 AM   #842
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8' grounding rod...that does sound like a PITA...haha. But probably worth it.

I should probably keep this question for the Where to Buy forum, but I'm having trouble finding a place to buy ground wire (copper or aluminum), lightning arrestor, and ground rod. I don't even know where to start looking - what type of local or online suppliers should I be searching for each of those things?

Feel free to PM me with specific supplier names...
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Old 2012-03-20, 11:30 AM   #843
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jmrudow, you will need 2 Ground clamps (one for the mast and one for the grounding rod). You could run the same wire through the grounding block, but I prefer having separate wires to the grounding rod (you can get away with 12 or 14 gauge to the grounding block).

I agree with Jase88 that a gas discharge lightning arrestor is a good idea. You can either get one with an integrated grounding block or get separate grounding block and lightning arrestors (but keep them close together).

It is also recommended that you have a wire run between your grounding rod and your electrical ground to keep them at the same potential.
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Old 2012-03-20, 11:34 AM   #844
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Quote:
Originally Posted by balm View Post
is this considered adequate, using 2 separate ground rods, at different locations, each for its own purpose ?
You could do that, but I would recommend running a wire between the two grounding rods to ensure they are at the same potential. You will also want to run a wire from the grounding block grounding rod to your electrical ground for the same purpose.
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Old 2012-03-20, 02:59 PM   #845
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Quote:
Originally Posted by roger1818 View Post
jmrudow, you will need 2 Ground clamps (one for the mast and one for the grounding rod). You could run the same wire through the grounding block, but I prefer having separate wires to the grounding rod (you can get away with 12 or 14 gauge to the grounding block).

I agree with Jase88 that a gas discharge lightning arrestor is a good idea. You can either get one with an integrated grounding block or get separate grounding block and lightning arrestors (but keep them close together).
Ahhhhh, I didn't realize the mast had to be grounded in addition to the coax! Okay, I think this is starting to make sense. I drew a little diagram, with one ground wire running from the mast through the block / arrestor down to the grounding rod:



Quote:
Originally Posted by roger1818 View Post
It is also recommended that you have a wire run between your grounding rod and your electrical ground to keep them at the same potential.
Hmmm...I'll have to find the electrical ground in my house. We're an inside unit in a row of townhomes - the grounding rod will be in my backyard, but I have a feeling the electrical ground is towards the front of the house...Our air conditioner is in the backyard, any chance that would be grounded, and I could "splice" into its grounding wire? haha...I may be grasping at straws here.
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Old 2012-03-20, 03:12 PM   #846
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Many houses use the water pipe entering their house as the electrical ground, so check your basement first.

Your diagram looks pretty good. You can find another in post #263.
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Old 2012-03-20, 04:26 PM   #847
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Roger,

Thanks, I kind of suspected that. OK, so there is no advantage in doing as I suggest (the original idea was to minimize the ground wire length, the shortest distance being from the roof to ground being where I was suggesting
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Old 2012-03-20, 04:43 PM   #848
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Minimizing the length of cable to ground isn't a bad thing.
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Old 2012-03-22, 08:52 AM   #849
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1. I was considering if we connect the antenna ground rod to the ground wire leaving the electric panel inside the basement wall, if this can cause any issues when lighting strikes....can the energized ground wire cause any damage to the electrical panel or any other interior item, like along the plumbing system when connected to that...?

I assume not, since the idea of the ground wire is to pass that extra energy down into the ground first!

2. In the case where it is highly impractical to connect the antenna ground rod to the house ground system (inside or outside), are there other alternatives ? or do most people just not connect the 2 systems together ....? (as is typically done around here! and NO, im not saying thats good !)
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Old 2012-03-24, 07:50 PM   #850
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A direct lightning strike plays by its own set of rules. No matter how well grounded things may be, if the sudden burst of energy is enough to arc over the safety measures it will do exactly that. If some or most of the energy is diffused by the ground wire(s) and rod(s) then that's all you can ask for. In industrial areas and most urban locations if a breaker or fuse is arced over then the electrical grid will take some of that load back over the return line and normally dissipate it over the grid before it can harm another location. In rural locations the grid might not be robust enough to drain much of it away. In North America if the local electrical grid goes down during a lightning storm it is usually because 3 quick tries were automatically made to absorb the increased energy before the safeties kicked in and shut it down.

As we've said many times in this thread, survival from lightning strike damage is not the prime reason for grounding. The purpose of grounding your OTA/Dish/CATV/Telecom gear is to dissipate unwanted electrical charges from damaging any of your gear.

If you cannot bind 2 or more ground rods together then there is always the possibility of an energy difference between the electrical ground states of each location, particularly if the local earth is not good at conduction. If the earth is generally damp or metallic between the ground rods it will hopefully conduct well enough between them, but still a direct wire from one to the other(s) is always best.
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Old 2012-03-24, 10:48 PM   #851
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great, thanks, will do .
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Old 2012-03-26, 04:41 PM   #852
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The other thing to remember is a direct strike is unlikely. Much more likely is a near miss, which can still cause major havoc if your system isn't grounded properly. A lightning strike on a nearby tree, house, pole, etc. can induce a large current in your antenna, mast and wires. This current should be directed to ground.
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Old 2012-03-30, 03:26 PM   #853
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I'm going to do some more research into tying my antenna ground directly into my air conditioner's ground (which is already directly connected to my house's main ground). Benefits:
- easier than banging a ground rod into the backyard (the air conditioner is only a few feet from where I would've installed the rod anyways)
- leaves my house with only one ground (i.e., no danger of the antenna ground and the house ground having an energy difference)

Drawbacks:
- potentially unsafe? I need to do some more research to see if there are any dangers to this...
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Old 2012-03-30, 05:14 PM   #854
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^^^^
Unsafe? Youbetcha and also illegal. Grounds must be separate all the way back to the common ground point. If there's a fault in the air conditioner's ground, you'll be bringing the strike right into your house and house wiring.
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Old 2012-03-30, 06:50 PM   #855
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Ahhhhh, good to know - definitely won't do that then.

So, now it's back to the grounding rod. I need to find a place that sells 8-foot grounding rods...
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