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post #1 of 17 Old 06-13-2011, 04:23 AM - Thread Starter
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Since I got such good advice on one antenna-related question here yesterday, let me ask another. The installers who put in my antenna didn't do a great job of grounding it. They put in a run of about 14 gauge wire from the antenna to the grounding block, then another from the grounding block to a piece of rebar that was barely in the ground. I replaced the rebar with a 4' grounding rod, but then when I had an electrician at the house for a different job I talked to him about it and he disconnected my grounding rod and ran a length of 14 gauge from the grounding block to the breaker box and house ground. That is better, I'm sure, but the more I read, the more nervous I am that I need a better quality grounding wire (and one that eliminates the sharp bends that I have now). Basically I've got two choices... better wire from the antenna (rooftop) run down to the breaker box/house ground or better wire from the antenna down to a separate grounding rod. Which of these is preferable?
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post #2 of 17 Old 06-13-2011, 05:48 AM
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Quote:
Originally Posted by Dimdem View Post

Since I got such good advice on one antenna-related question here yesterday, let me ask another. The installers who put in my antenna didn't do a great job of grounding it. They put in a run of about 14 gauge wire from the antenna to the grounding block, then another from the grounding block to a piece of rebar that was barely in the ground. I replaced the rebar with a 4' grounding rod, but then when I had an electrician at the house for a different job I talked to him about it and he disconnected my grounding rod and ran a length of 14 gauge from the grounding block to the breaker box and house ground. That is better, I'm sure, but the more I read, the more nervous I am that I need a better quality grounding wire (and one that eliminates the sharp bends that I have now). Basically I've got two choices... better wire from the antenna (rooftop) run down to the breaker box/house ground or better wire from the antenna down to a separate grounding rod. Which of these is preferable?

Ideally, you want to run minimum #10 bare copper wire from the antenna to grounding block, then down to the electrical box ground rod going into the ground. Very important that if there are 2 grounding rods involved, they should be bonded together with the same #10 wire to keep same ground potential.

I was lucky with mine, the antenna and outside meter were on the same side of the house, so my ground wire came down side of house to the ground rod . I used a seperate ground rod clamp. Do not tie the ground wire to an existing clamp with a wire in it.
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post #3 of 17 Old 06-13-2011, 08:29 AM - Thread Starter
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I don't have access to the house's ground rod, as it is under a cement patio. Of course I can tie into the house ground, but only by going through the box.
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post #4 of 17 Old 06-13-2011, 10:42 AM
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Originally Posted by Dimdem View Post

I don't have access to the house's ground rod, as it is under a cement patio. Of course I can tie into the house ground, but only by going through the box.

Well that's better than nothing.
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post #5 of 17 Old 06-13-2011, 11:45 AM
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Quote:
Originally Posted by mikepier View Post

...if there are 2 grounding rods involved, they should be bonded together with the same #10 wire to keep same ground potential....

The two rods must be connected to one another with #6 gauge copper wire to conform to "code".
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post #6 of 17 Old 06-13-2011, 01:16 PM
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Originally Posted by AntAltMike View Post

The two rods must be connected to one another with #6 gauge copper wire to conform to "code".



I stand corrected, thank you.
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post #7 of 17 Old 06-13-2011, 02:39 PM - Thread Starter
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Quote:
Originally Posted by mikepier View Post

Ideally, you want to run minimum #10 bare copper wire from the antenna to grounding block, then down to the electrical box ground rod going into the ground. Very important that if there are 2 grounding rods involved, they should be bonded together with the same #10 wire to keep same ground potential.

Quote:
Originally Posted by AntAltMike View Post

The two rods must be connected to one another with #6 gauge copper wire to conform to "code".

Just to be clear, if I use a separate ground rod but the coax (via the grounding block) and mast are both grounded to it, would it still need to be bonded to the house ground? If the answer to this is yes, then I think that my best bet is just to use a thicker ground wire than I have now and have an electrician ground it through the box. I assume that there is no adequate way to attach the ground wire from the antenna directly to the bare ground wire that runs from the box to the rod.

I'm really irritated over this whole situation. I don't claim to know much about this stuff, so I hired pros: first a company that advertises itself as being knowledgeable about antenna installations, and then an electrician. I had the electrician install a new house ground; we just had a cold water ground before, and I had him install a 10' rod. This was before the patio was poured; we just got it last week. He could have charged me what he wanted to do job right. And yet after paying people who are supposed to know what they are doing, I feel like I still have an unsafe situation.
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post #8 of 17 Old 06-13-2011, 04:18 PM
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If you have a separate ground rod for your antenna system, the antenna mast and the grounding block each need to be connected to it with separate No. 10 copper wires, and the ground rod needs to be connected (bonded) to the house electrical ground with No. 6 copper wire. The grounding rod must be at least 8 ft long.

If you don't have a separate ground rod, and use the house electrical ground for your antenna system, you only need the two No. 10 copper wires.

No. 14 gauge wire is OK for the cable guys, but not for OTA antennas. A 4 ft ground rod is not long enough for the 2008 NEC; I haven't seen the new 2011 code book yet. Go to the library and look at the 2008 NEC code book; Article 810 is for OTA, Article 820 is for cable.

We covered this topic pretty well in this thread:
Grounding Antenna and Dish
http://www.avsforum.com/avs-vb/showthread.php?t=1333059

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post #9 of 17 Old 06-13-2011, 06:09 PM - Thread Starter
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Is it acceptable if the antenna and grounding block attach to the house ground in the box, or do they need to run straight to the ground rod? Because, as I said, that is now covered with a new patio. If it is now impossible for me to ground the antenna safely I'm going to have to go back to cable, and that is freaking going to make me mad given that I had an electrician look at this before the patio was in place.
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post #10 of 17 Old 06-13-2011, 06:59 PM
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Quote:


Is it acceptable if the antenna and grounding block attach to the house ground in the box.....

I think the answer would be YES (but ON the box, not IN the box), but I'm not an electrician. The final say would be by your local electrical inspector (also known as AHJ....authority having juristriction), but you might not want to get him involved.

Go to the library and read 2008 NEC article 810.21(A) through (K) Grounding Conductors, and in particular 810.21(F)(2) which gives the alternative electrodes for connecting the No. 10 grounding wires from your antenna system.

Some of them are illustrated here in Part 2 of 8, but Mr. Humphrey's interpretation should not be considered the official NEC position on grounding:

Satellite System Grounding
Part 2 - NEC Overview
Presented by Todd Humphrey
http://www.dbsinstall.com/diy/Grounding-2.asp

In the 2008 NEC book 810.21(F)(2) In Buildings or Structures with Grounding Means, the following two seem to apply to your situation:

(5) The service equipment enclosure (with the added note: "A bonding device shall not be mounted on a door or cover even if the door or cover is non-removable.")
(6) The grounding electrode conductor (maybe with a split bolt/bolts?) or the grounding electrode conductor metal enclosures

Quote:


Basically I've got two choices... better wire from the antenna (rooftop) run down to the breaker box/house ground or better wire from the antenna down to a separate grounding rod. Which of these is preferable?

I think "... better wire from the antenna (rooftop) run down to the breaker box/house ground..." would be OK if it's No. 10 gauge mast and coax grounding block wires. If you used the second option of the separate grounding rod for the antenna system, you would still need to connect that separate rod to the house electrical system ground with No. 6 copper wire.

I have used the terms "wire/wires" and "split bolt/bolts" because the NEC only allows one wire to be attached with an approved device. If there are two No. 10 gauge grounding wires, then two attachment devices are required.

Does that make you feel a little more hopeful?

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post #11 of 17 Old 06-13-2011, 07:02 PM
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Quote:
Originally Posted by Dimdem View Post

Is it acceptable if the antenna and grounding block attach to the house ground in the box, or do they need to run straight to the ground rod? Because, as I said, that is now covered with a new patio. If it is now impossible for me to ground the antenna safely I'm going to have to go back to cable, and that is freaking going to make me mad given that I had an electrician look at this before the patio was in place.

I would not lose sleep over it. What you did was the next best thing.
I can't tell you how many antennas in my neighborhood are not grounded.

Keep in mind, the whole reason for grounding your antenna is to discharge any static electricity that might accumalate on the antenna from winds blowing on it during a thunderstorm. The static electricity would attract lightning to the antenna.

Even a properly grounded antenna is not going to prevent a direct lightning strike from damaging a home. But it will decrease the chances of it happening.
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post #12 of 17 Old 06-13-2011, 11:59 PM
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There is nothing wrong with grounding to a cold water pipe except that it does not meet the letter of the code. The reason that it does not meet the code is that, with so much modern plumbing repair using plastic repair sections, the powers that be have decided that the likelihood that a copper water pipe ground path may become disrupted in the future due to a plastic repair was sufficient reason to exclude it from the approved connection point list, but a copper water pipe was and is a very good ground point if you know it to be continuous back to the ground electrode system.

You are not allowed to run your ground wire "in the box", but you may attach a ground wire to the outside of a box. There are little attachment do-dads, like box corner clamps, that are made for that purpose.

The term "service panel", which is sometimes called an acceptable attachment point, may be ambiguous. I think that term is a leftover from way back when we used fuses rather than circuit breakers and the first stop for the power once it had passed through the meter was a box with two big sucker cartridge fuses in it. That was called the service panel. From there, it went to another box with the round, screw-in glass fuses. Now we use one box that combines both of those functions, and so I guess that is now the service panel, and so you can attach your ground wire to a brass fitting that is attached to that metal enclosure, but not only are you NOT allowed to run your ground wire into it, you are not allowed to wrap your ground wire under the head of any of the screws that are used to attach the cover to the box, because any ground clamp is only allowed to serve the purpose of clamping one ground wire and doing nothing else.

It appears that the term raceway is commonly interpreted to include the conduit that goes from the meter box to the circuit breaker panel.

And as far as "Todd Humphrey", cited above, is concerned, he is simply another internet contributor like us who is or was so fascinated with the subject of grounding that he dedicated his own website to it. He used to maintain some kind of service connecting people who wanted custom system installations to "approved" independent satellite system installers (approved by him), but I don't know him to be a licensed electrician or to have any other relevant, professional certification. In other satellite TV antenna and broadcast TV antenna installation internet threads, Mr. Humphrey has often "reasoned", to his own satisfaction, why a grounding rule exists and then pronounced certain practices to be acceptable or unacceptable based on that reasoning, but those are just his own opinions.
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post #13 of 17 Old 06-14-2011, 05:59 PM
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Quote:
Originally Posted by mikepier View Post

I would not lose sleep over it.

Good advice. There are several easy ways to solve your grounding problem.
Quote:


I don't have access to the house's ground rod, as it is under a cement patio.

I don't think the NEC says that is the only place you can connect your antenna system grounding wire/wires.

AntAltMike:
Thanks for the background information on Todd Humphrey, and your opinions on the grounding problem based on your hard-won experience with electrical inspectors and many antenna installations.

I have edited my post #10 based on your advice. Please let me know if it needs further editing. I have no desire to give bad advice to posters who have grounding problems, and prefer to quote the official NEC position and let the posters decide what shortcuts they are willing to take.

Dimdem:
Please let us know how the amp, splitter, and grounding problems work out.

If you can not measure it, you can not improve it.
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post #14 of 17 Old 06-15-2011, 04:30 AM - Thread Starter
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Good advice. There are several easy ways to solve your grounding problem.
I don't think the NEC says that is the only place you can connect your antenna system grounding wire/wires.

AntAltMike:
Thanks for the background information on Todd Humphrey, and your opinions on the grounding problem based on your hard-won experience with electrical inspectors and many antenna installations.

I have edited my post #10 based on your advice. Please let me know if it needs further editing. I have no desire to give bad advice to posters who have grounding problems, and prefer to quote the official NEC position and let the posters decide what shortcuts they are willing to take.

Dimdem:
Please let us know how the amp, splitter, and grounding problems work out.

Will do. I've got a splitter coming to me from Amazon. (Also an attenuator, just play with, because it was cheap.) We're just starting a kitchen remodel today that will have electricians doing various jobs, and I mentioned what I needed to the contractor yesterday. He said that he thought he could have his electricians take care of it for me. He'll have to pull permits and have inspectors out, so he's all for my being up to code. The new worry might be that my service panel is so full that I'll need a new one, but that's a story for another forum. Thanks all for your help.
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post #15 of 17 Old 06-15-2011, 10:33 AM
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Thanks for letting us know how you are doing, my friend in Norfolk. It sounds like they will be able to do a proper job that will let you sleep at night!

Based on your description of your grounding problem, I was only able to identify two possible easy solutions. I might have overlooked other possibilities. Having photos of an installation makes it a little easier, as shown in this similar case history that you might find interesting:

ground antenna question
http://www.avsforum.com/avs-vb/showthread.php?t=1244323

If you can not measure it, you can not improve it.
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post #16 of 17 Old 06-15-2011, 12:07 PM
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Quote:
Originally Posted by rabbit73 View Post

Thanks for letting us know how you are doing, my friend in Norfolk. It sounds like they will be able to do a proper job that will let you sleep at night!

Based on your verbal description of your grounding problem, I was only able to identify two possible easy solutions. I might have overlooked other possibilities. Having photos of an installation makes it a little easier, as shown in this similar case history that you might find interesting:

ground antenna question
http://www.avsforum.com/avs-vb/showthread.php?t=1244323

Yes, I started that thread. Learned a lot from my first time grounding the antenna.
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post #17 of 17 Old 06-16-2011, 03:59 AM
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It also matter where you are regarding the likelihood of being hit in the first place.
In the city the likelihood is low, out in the 'sticks' it is very high. The further out you are, the higher you are and the more 'open' you are you need some serious protection.

Abundant OTA television is what makes this country different from all others. Lets keep it this way.
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