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I'm about to install an Over The Air (OTA) antenna as the first phase of cutting the cord.

I understand the antenna and coax cable need to be grounded. I can purchase and drive a grounding rod where the coax enters the house and connect the coax and mast ground lines to that grounding rod no problem.

The thing that's preventing me from going forward with the job is that I'm not sure how to then bond the antenna grounding rod to my home electric ground. I've read that this should be done with a 6 AWG copper wire, but I was planning on routing the coax into my house where my satellite coax currently enters, which is on a different side of the house from my water pipe and my breaker box.

Of course the satellite installer didn't ground the dish or the coax cable, so I can't reuse any of that.

Is it okay to have the jumper from antenna ground to home electric ground just laying on the dirt outside the house? My concern is that I don't want to bring a (probably) unsheathed conductor, whose entire purpose is to carry lightning, into my house. I had read something online about not having the bonding wire within some distance of the soil, but that didn't reference any NEC codes.

I just want to do this right so I don't set my house on fire. Lightning running down a 6 gauge wire routed through my walls seems exactly like how that would happen, but I'm not sure how else to attach the two grounds.

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    From memory all the grounding electrodes are supposed to be inter connected. #6 copper can be routed outside the house to the existing electrode without additional protection (or through the crawl space). – Ed Beal Sep 16 '16 at 15:10
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The purpose of an earthen ground is not to direct lightning. It's unlikely that you'll have lightning running down a wire routed through your walls, unless you have other more severe electrical problems in your residence. Your home's electrical wiring should have a current earthen ground "somewhere" and all devices using that electricity are conductive to that ground.

Having an independent earthen ground in the manner you describe ensures that your additional device, in this case, an antenna has the electrical potential set to match the rest of the system. If you did not have an earthen ground for the antenna and received outside electrical impulse (lightning), the charge would then attempt to travel through the signal cable into the electronics attached to the antenna and from there, through your house's electrical ground to the earthen ground. It's unlikely it would travel that far, however, as the electronics would take the brunt of the force and go up in smoke.

An independent earthen ground provides for a safer path for the antenna, the mast of which should be bonded to the ground. You can also bond the coax from the antenna to that ground with a grounding block. If you have satellite coax without a grounding block, install one and bond it to the same ground.

There is no reason to run the ground wire into the house, unless you have devices within that are not grounded to the house ground system.

The primary objective is to have every device at the same electrical-potential-level of the ground rod. The outer conductor of the coax will provide suitable ground connection to the electronics within, for both the satellite equipment and the OTA equipment.

If you were to take a severe enough strike on your antenna mast that the earthen ground could not safely dissipate it, and the "excess" traveled on the coax, it would likely melt the coax and prevent travel into the house. As a former cable television technician in Florida, I found many instances where the house ground was not bonded to the cable tv block ground. The lightning strike/surge that traveled into the residence on the power line exited on the cable tv ground, burning up the electronics in the television. Back in the 80s, it wasn't practice to bond the house and cable tv grounds together. That has since changed and destroyed television are rarer now.

Regarding the ground wire running in the dirt, it's not going to change anything with respect to electrical potential. I don't know NEC codes, but I'd be surprised if there was anything of concern there. If you could drive #6 copper straight down 8 feet, you'd have suitable grounding. It's easier to hammer in a 1/2" rod though.

  • Electricity follows every available path. If there's a lightning strike, the current will flow on both the ground and the coax cable. However, since the ground has a lower resistance, the current along that path will be higher. If there's a lightning strike, it's not likely that a 6 AWG ground wire will save your electronics. – Tester101 Sep 16 '16 at 15:27
  • I agree with the lightning strike destroying the electronics. It's the "ambient atmospheric" electrical charge that would be more of a concern with a nearby strike than with a direct hit. I read a study in a real magazine, the paper type, about a "metallic christmas tree" with sharp pointed needles, placed on a tower with an ammeter connected to it and ground. As a storm moved closer, the current increased substantially, while the tree bled of the energy of the air surrounding the tower. Lightning rods are single points, while this tree was hundreds of them. – fred_dot_u Sep 16 '16 at 15:41
  • It was determined in the study that one tree on one tower with a good ground provided lightning elimination(!) for the space surrounding the tower as much as one-quarter mile radius. Zero strikes because the potential necessary for a lightning strike was bled off rather than accumulating. Current measurement of the conductor during approaching storms also held up the concept of dry air lightning being a serious concern. Florida has strikes up to three miles away from storm centers that kill people! – fred_dot_u Sep 16 '16 at 15:44
  • Okay, so to summarize, any lightning that strikes the antenna should go directly to the grounding rod under the antenna. The bonding wire can just lay on top of the soil as it routes around the exterior of my house where it will clamp onto the ground wire for my exterior electrical service box. The bonding wire only exists to keep the antenna ground at the same potential as my electrical ground so induced current from nearby lightning doesn't choose to route through my TV to get to ground faster. Is everything I said correct? – Chuck Sep 16 '16 at 17:41
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    Any lightning that strikes the antenna will cause damage throughout your house, regardless of the quality of the bonding and earthen grounds. Lightning that strikes nearby or power surges you receive via the power line will send maximum current to the ground with the least resistance. Your last statement is mostly correct. I would suggest to secure the wire either by burying it slightly or attaching it to the wall. My rotary grass trimmer really likes to wrap around even slightly exposed wiring. – fred_dot_u Sep 16 '16 at 18:27

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