OTA grounding

[jrv331]

I have a few questions on grounding. I think it might be to much to post, so if any of you could help me out and do via private message I'd apprecieate it.
Thanks for al the previous help. This is a great group.
John

 

[gpflepsen]

When exchanges take place here in public, it benefits the group as a whole.

What's the problem?

 

[jrv331]

OK,
I know I have to ground my antenna and mast with bare #8 copper wire. Can I use coated/insulated #8 instead? Also do I have to ground both the antenna and mast? Wont grounding the just the mast do the trick?
Thanks
John

 

[ROLLTIDE]

I grounded mine into the Gulf Of Mexico

 

[gpflepsen]

I grounded mine into the Gulf Of Mexico

How many feet of wire did you have to run?

 

[gpflepsen]

OK,
I know I have to ground my antenna and mast with bare #8 copper wire. Can I use coated/insulated #8 instead? Also do I have to ground both the antenna and mast? Wont grounding the just the mast do the trick?
Thanks
John

You can use any copper conductor, insulated or not. If it is insulated, some form of identification should be used to denote it's a ground. Green would do the trick. Why #8? Unless code calls for #8, I wouldn't worry about it. #12 or #14 will do fine. Ground the mast to the house's electrical ground. If that's not possible, an eight foot copper ground rod needs to be driven into the ground.

This brings us to the actual need to ground the antenna. Some swear by it, and others swear against it. It has to do with the grounded antenna being more of a lightning attractor. A #8 ground wire isn't going to protect squat if it's hit by lightning.

 

[ROLLTIDE]

Actually it is grounded into a river that runs into the bay and the bay runs into the gulf

20 ft of wire And now have my panamax 5100 hooked up so I am ready for summer storms

 

[jrv331]

One of the NEC sites mentioned to use no smaller than #10. I have about 50ft of coated #8 from a previous project.Im installing the antenna on the opposite side of my house from the main ground. From what Im undertanding I have to ground the mast into a a new rod then connect that rod to the main rod using #6 wire. Im not sure if its more for lightening protestion or static discharge.
Thanks
John

You can use any copper conductor, insulated or not. If it is insulated, some form of identification should be used to denote it's a ground. Green would do the trick. Why #8? Unless code calls for #8, I wouldn't worry about it. #12 or #14 will do fine. Ground the mast to the house's electrical ground. If that's not possible, an eight foot copper ground rod needs to be driven into the ground.

This brings us to the actual need to ground the antenna. Some swear by it, and others swear against it. It has to do with the grounded antenna being more of a lightning attractor. A #8 ground wire isn't going to protect squat if it's hit by lightning.

 

[red hazard]

You can go up to a thicker wire (down numerically in gauge) but you are in violation of the NEC if you go to a smaller wire like 12 or 14 gauge. I use 6 gauge on my TV antenna mast. The theory, and it's contraversial, is that the electrons stream off a grounded antenna system into the positively charged clouds which helds reduces the amount of static charge differential and thus decreases the chances of a lightning strike. The NEC isn't a fairy tale.

 

[Carl B]

...and lightning doesn't follow the Code, but it does preferentially like narrow vertical objects that signicantly break a flat plane. That is, if the terrain around you is fairly flat, the house roofs are fairly flat, there are few trees and they aren't extremely tall or they are at least very broad, then an antenna you mount on a mast that is ten or more feet above your roof is a lightning target. Grounding won't change that! However, sufficient grounding may minimize the damage a lightning strike may cause to your house and grounding to Code will allow you to sell your house w/o having to spend money to upgrade to Code at that time.

 

[M Law]

...A #8 ground wire isn't going to protect squat if it's hit by lightning.

It's going to prevent the lightning from traveling into your house and possibly burning it to the ground. The coax and mast should both be grounded. The point is not to protect equipment but to prevent it from coming into the house.

 

[gpflepsen]

OK, let's get nasty

I agree wholeheartedly with grounding to code. Lets say the antenna is struck and the mast is electrified. The antenna conductor will be electrified also. Who makes a surge protector which will handle a lightning strike? I'm sure many out there are guaranteed to work but they won't handle this situation. You can now kiss your equipment goodbye. Anything connected to the antenna will be damaged. That's the squat I'm talking about.

Grounding the mast will provide one path to ground, but the current will find other paths too. Some will go through the house to the foundation. How much is up to the individual lightning strike. How good is the ground rod in the ground? A lightning strike will give the ground rod a potential depending on the voltage cone formed in the soil. You can be killed standing 5' away from the ground rod when the lightning strikes the antenna 50' away.

My personal opinion is that grounding the mast makes it even more attractive to lightning strikes. I'd prefer to have lightning rods installed and an ungrounded mast. Or, if possible, to mount the antennas in the attic, which is what I am able to do. In any case, have insurance to C.Y.A Which is another reason to have the local code followed.

Hmmmm... is there a market for a fiberglass antenna mast?

 

[jrv331]

Do they make inline surge protectors for cable?
You guys have provided a wealth of information,
Thanks
John

OK, let's get nasty
Who makes a surge protector which will handle a lightning strike? I'm sure many out there are guaranteed to work but they won't handle this situation. You can now kiss your equipment goodbye.

 

[gpflepsen]

There are surge protectors and lightning arrestors. I don't think you can buy cable surge protectors which will protect your equipment from lightning. Your equipment would probably get fried. Lightning arrestors work by protecting your house from major damage, like fires started because of the heat from hot wires.

Surge protectors use electronics to dampen voltage spikes in the electrical system. Lightning will just fry these. Lightning arrestors work like spark plugs hooked to the wiring. There is no direct path to ground, but during a lightning strike, the gap in the plug becomes conductive and carries the brunt of the strike to ground.

Surge protectors will probably save from surges, arrestors probably won't save from strikes.

They do sell surge protectors which have antenna connections.

 

[M Law]

Sorry gpflepsen if you took that as being nasty, not intended that way. No one said the purpose of grounding is to protect your equipment, it's not. The ground wire would have to be of a massive size to actually protect electronics, and it's just not possible. You stated that a gorund doesn't protect squat, and it does.

Using a grounding block on the coax will help in shunting a strike to the ground rod and preventing the lightning from possibly causing a fire inside the home. It will not prevent lightning from frying the gear, that's not its purpose.

The debate over whether installing a ground increases the potential for a strike has a long and storied history. I don't think we are going to create the definitive discussion here, I know I am not that qualified. Having exposed metal attached to the exterior of your house invites lighting no matter what IMHO, so why not provide that energy a path to ground and keep as much out of the house as possible? It's not that difficult to install a ground in most cases, so why not take that simple precaution?

But I do know for a fact that if you do not properly attach an incoming conductor to the grounding grid of the facility at the exterior entry point you run the risk of enough energy entering the facility to start a fire. I've seen it happen at work, among other lightning events I've witnessed.

jrv331, we started a discussion of surge suppresion and other power related issues in this thread:
Surge Suppression and Power Conditioning

I am ordering 6 DLPS-SAT1's for the coax that enters my house, let you guys know when they are installed and how well they pass signal.

 

[DishBacker]

gpflepsen, you mention that you prefer installing antennas in the attic. I have one in the attic, just hanging from the rafters by some string. Is there any need to have this setup grounded? We recently had a 'near lightning strike' that did some damage to one of my AC unit's control boards and the connected thermostat, in addition to a phone and my Dish Network 501 modem. So, now I'm wondering if I need a ground on the antenna, as its above my second story, a good 23 ft into the air with only other 2 story houses around me... no tall trees, etc.

 

[slacker9876]

Use 14GA THHN, this complies with the National Electric Code. After a Voom install my OTA was arcing to the SAT outlet at the wall during an electrical storm. Grounding for satellite dishes and OTA antennas is mainly for the transient voltage that runs through the air. You will sustain damage from a direct strike grounded or not, however, there is no point in "drawing" a strike. Also if you are grounded, close and/or direct strikes, have a path other than though your home … this is a good thing.

 

[rhasselbaum]

Hi all. I just moved my OTA antenna to a mast over the roof, and now I'm trying to ground the mast. Found this thread, but I still have questions.

How does one usually gain access to the house's electrical ground from the roof? Can I run a copper wire all the way to the same exterior grounding block that the antenna is attached to? That would involve running the wire along the side of the house a fair distance (around 50 feet). Is that wise? What type of wire should I use for that distance? Can the wire be attached with regular electrical tape?

Thanks.

 

[Cokeswigga]

I have yet another grounding question.

I found the house main electrical ground.
It's a 8-gauge bare copper wire that runs from my meter at the front of my house through the attic to water heater at the rear of my house, and connects to to the cold water pipe and the natural gas pipe.

I connected a 8 guage bare copper wire at the base of the mast (which is attached to the eve and the patio cover) and ran it to the eve where the rg-6 grounding block is, and then into the attic to attach to the existing 8 guage wire in the house.

Is this a correct way to ground the mast and antenna, or is there something else I should do? Or is there a better what to do this?