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I want to mount a TV antenna on my shed in my back yard and run the wire underground to my house. The shed is about 60 to 70 feet from the house. There is electrical service in the shed, but there is no ground rod at the shed that I know of (I figured I would have to put one there).

Google has led me to a lot of explanation of grounding with the antenna on the house and it states that you should have a grounding block close to where the cable enters the house. I am wondering if in my situation if it would be okay to have the grounding block at the bottom of the shed where the wire enters the ground.

Also, are there any other differences I want to consider when running an antenna from my shed to my house. I am planning on putting the underground wire in PVC.

  • It's easier to install on the house, because then you don't need an additional grounding electrode, or to bond the electrodes. – Tester101 Sep 22 '14 at 15:39
  • By electrical service at the shed, do you mean a single (or multi-wire) branch circuit, or a feeder and a panel? – Tester101 Sep 22 '14 at 15:40
  • I don't know enough about electrical to know what you just asked (the electrical service was already there when i bought the house). At my service panel in my house there is a breaker for the shed. At the shed there is a little panel with a single switch(breaker?) to turn the entire shed power off. From there it branches to a few outlets and a light switch. – Mike Sep 22 '14 at 15:47
  • @Mike The reason I ask about the electrical service in the shed, is because if there's a panel, there might already be a grounding electrode. If there is a green or bare wire going away from the panel, follow it and see if it connects to an electrode. – Tester101 Sep 23 '14 at 11:58
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At the shed

Grounding Electrode

The first thing you'll need to do, is to install an approved grounding electrode at the shed. For this answer, I'll assume a 5/8" x 8' grounding rod will be installed.

Bond the Mast

You'll have to bond the mast of the antenna to the newly installed grounding rod, which you'll do using a 10 AWG copper conductor. You'll attach the #10 conductor to the ground rod, using a fitting approved for the purpose. This fitting is only allowed to attach this single wire to the rod, so you can't use it to attach multiple wires.

Bonding the Electrodes

A bonding jumper of not less than 6 AWG copper (or equivalent) should be connected between this new ground rod, and the grounding electrode of the house.

Grounding the Cable

You'll want to run a coaxial cable with a built-in ground wire, from the antenna to the house. Otherwise you'll have to pull a 10 AWG grounding conductor along with the cable.

At the House

Connect the Cable

The coaxial cable should be attached to an approved Antenna Discharge Unit, before it enters the house.

NOTE: When shopping for an Antenna Discharge Unit, you'll want to look for a device that is listed to comply with ANSI/UL 452 "Antenna - Discharge Units".

Grounding

How the cable and ADU are grounded, completely depends on your grounding system. I'll cover two common methods, which should give you a good idea of how to handle it.

Intersystem Bonding Termination

The easiest method, is if your house has an Intersystem Bonding Termination. This is typically a terminal affixed to the outside of the service equipment enclosure, or a terminal on the outside of the house that is connected to the service equipment. In this case, you'll simply attach the ADU and cable grounding conductor to the IBT.

Grounding an Antenna IBT

Grounding Electrode

If there is no IBT, you can connect the grounding conductors to the grounding electrode at the house.

Grounding an Antenna no IBT

No Intersystem Bonding Termination or Grounding Electrode

If your house is really old, you might have neither an Intersystem Bonding Termination, nor a Grounding Electrode. In this case, you can use any of the approved grounding electrodes described in the National Electrical Code article 250.52.

  • Aside from that the code calls for it, what is the reason for connecting the two ground rods? It seems to me that, assuming the coax is grounded to the shed's rod, the two systems are completely independent, just like two separate houses. (I'm assuming that the electrical system in the shed is NOT grounded to the rod at the shed. If it is, then I do understand why the two ground rods have to be connected.) – Marc Rochkind Jan 31 '15 at 1:12
  • The voltage potential in the earth varies from one place to the another, even over a short distance. Bonding the two locations keeps them at the same electrical potential. All the voltage in your home is in reference to ground potential (0). If "0" is different throughout the electrical system, you could run into problems. Bonding the two electrodes allows "0" to be the same everywhere. – Tester101 Jan 31 '15 at 1:51

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