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Author Topic: 12v battery and grounding  (Read 686 times)

KA1JNK

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12v battery and grounding
« on: December 08, 2020, 06:38:37 AM »

My shack will be 75' away from my AC panel and its ground rod. I can't bond station ground rod(s) to the panel.

My thought is to use a 12V battery to run my equipment, which right now is a 5W QRP rig, and hopefully an IC-7300 in the future. I could maintain the battery with a solar panel. Is this a good solution?

If this set up would work, what should my station ground system look like?
Thanks,
David
KA1JNK
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N2AYM

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Re: 12v battery and grounding
« Reply #1 on: December 08, 2020, 07:47:27 AM »

My shack will be 75' away from my AC panel and its ground rod. I can't bond station ground rod(s) to the panel.

My thought is to use a 12V battery to run my equipment, which right now is a 5W QRP rig, and hopefully an IC-7300 in the future. I could maintain the battery with a solar panel. Is this a good solution?

If this set up would work, what should my station ground system look like?
Thanks,
David

I view this maintaining a battery with a solar panel as a short term solution.
In the long term I would work on extending your ac to your shack.
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W9IQ

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Re: 12v battery and grounding
« Reply #2 on: December 08, 2020, 07:56:39 AM »

If your shack is not connected to the mains in the house, then you can keep your shack ground rod(s) isolated from the house ground system.

You should have one or more 8 foot ground rods at your shack. If you have more than one, keep them 16 feet apart and bond them together with 8 gauge or larger wire. These should connect to a lightning arrestor on your coax cable before it enters the shack. There is no need to separately ground your radio since there is no AC in the shack.

- Glenn W9IQ
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

KA1JNK

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Re: 12v battery and grounding
« Reply #3 on: December 08, 2020, 08:22:11 AM »


I view this maintaining a battery with a solar panel as a short term solution.
In the long term I would work on extending your ac to your shack.
I can easily string AC to the shack, I was all set to do just that but bonding the shack ground rods to the mains ground rod is not doable.
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KA1JNK

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Re: 12v battery and grounding
« Reply #4 on: December 08, 2020, 08:23:36 AM »

If your shack is not connected to the mains in the house, then you can keep your shack ground rod(s) isolated from the house ground system.

You should have one or more 8 foot ground rods at your shack. If you have more than one, keep them 16 feet apart and bond them together with 8 gauge or larger wire. These should connect to a lightning arrestor on your coax cable before it enters the shack. There is no need to separately ground your radio since there is no AC in the shack.

- Glenn W9IQ

Thanks. This is just what I was hoping I could do.
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N6MST

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Re: 12v battery and grounding
« Reply #5 on: December 08, 2020, 09:03:56 AM »

If your shack is not connected to the mains in the house, then you can keep your shack ground rod(s) isolated from the house ground system.

If your radio connects to a computer (or other equipment) that is running on house AC power you will want to assess this situation and apply proper grounding techniques.
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W9IQ

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Re: 12v battery and grounding
« Reply #6 on: December 08, 2020, 09:07:01 AM »

If your shack is not connected to the mains in the house, then you can keep your shack ground rod(s) isolated from the house ground system.

If your radio connects to a computer (or other equipment) that is running on house AC power you will want to assess this situation and apply proper grounding techniques.

True - if there is a galvanic connection between the house and shack then the situation changes. I didn't see that in the initial discussion but if this is needed, I would consider using WiFi, a control link or fiber optics to avoid the galvanic connection.

- Glenn W9IQ
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

AA4PB

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Re: 12v battery and grounding
« Reply #7 on: December 08, 2020, 09:50:00 AM »

I can easily string AC to the shack, I was all set to do just that but bonding the shack ground rods to the mains ground rod is not doable.
Why can't you run the bonding wire with the power wires? The requirement is that you bond the grounding systems, not that you actually run a bonding wire from ground rod to ground rod. If your shack is a separate building, you could just install a sub-panel in the shack building. Run a hot, neutral, and ground (or two hots, a neutral, and ground if you want 220V service) from the main panel in the house to the sub panel in the shack. Put in a ground rod at the shack and connect it to the sub panel.
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Bob  AA4PB
Garrisonville, VA

KA1JNK

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Re: 12v battery and grounding
« Reply #8 on: December 08, 2020, 10:42:37 AM »

I can easily string AC to the shack, I was all set to do just that but bonding the shack ground rods to the mains ground rod is not doable.
Why can't you run the bonding wire with the power wires? The requirement is that you bond the grounding systems, not that you actually run a bonding wire from ground rod to ground rod. If your shack is a separate building, you could just install a sub-panel in the shack building. Run a hot, neutral, and ground (or two hots, a neutral, and ground if you want 220V service) from the main panel in the house to the sub panel in the shack. Put in a ground rod at the shack and connect it to the sub panel.

Everything I am reading says that the two ground systems need to be bonded with a #6 grounding wire. I've also read that it needs to be buried around the house from one system to the other. If all I have to do is run some romex through the cellar between the grounds, that would make life simple.
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W9IQ

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Re: 12v battery and grounding
« Reply #9 on: December 09, 2020, 02:56:47 AM »

If you go that route, consider adding another ground rod or two in the trench itself. If you use exothermic bonding on the rods, you get a permanent buried connection and you can splice the bonding wire at each rod. Remember that #6 wire is the minimum, you can always go larger.

Using bare wire in a trench also helps to improve the ground system as it acts like a grounding electrode itself.

As AA4PB pointed out, you can also put a sub panel in the remote shack and then you don't need need to bond the grounding electrodes between the buildings.

- Glenn W9IQ
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

KA1JNK

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Re: 12v battery and grounding
« Reply #10 on: December 09, 2020, 07:06:26 AM »

If you go that route, consider adding another ground rod or two in the trench itself. If you use exothermic bonding on the rods, you get a permanent buried connection and you can splice the bonding wire at each rod. Remember that #6 wire is the minimum, you can always go larger.

Using bare wire in a trench also helps to improve the ground system as it acts like a grounding electrode itself.

As AA4PB pointed out, you can also put a sub panel in the remote shack and then you don't need need to bond the grounding electrodes between the buildings.

- Glenn W9IQ
Just to be clear, The shack is in the cellar of my house. The mains is on the south side and the shack will be  on the north side, 75' away. I watched this video last night https://www.youtube.com/watch?v=4RkiRwjK2oU&list=FL7q6wVWQsUSTGejlDWEfjMA&index=1 Grounding and Bonding for the Little Pistol and Medium Gun by Ward Silver, N0AX. There was a lot of good information especially about having to attach and bury a #6 ground wire with multiple ground rods from the mains ground rod to the shack ground rod. That would be very difficult to do in my situation.
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AA4PB

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Re: 12v battery and grounding
« Reply #11 on: December 09, 2020, 10:14:26 AM »

I agree that as the video shows, it is best to bury the #6 bonding wire outside of the house. However, that is often not very practical. The NEC allows the bonding wire to be run either inside or outside of the house. The important point is that all ground connections within a building are connected together so that they remain at the same reference voltage and do not create a shock hazard if someone comes in contact with two different grounds. It's the same reason that the NEC requires metal (conductive) plumbing pipes to be bonded to the electrical system ground. Bonding simply means a permanent connection. Removable plugs/sockets or other devices that could be easily disconnected by a user are not permitted in the bonding connection. The NEC also does not require that the bonding wire be connected directly to the ground rods. It requires that the grounding "systems" be bonded so you can attach to the rods (which is often done) or to the grounding system conductors.

If I were in your situation, and I could get a #6 conductor from the shack to the electrical panel inside the house that's where I would run the bonding wire. You'll probably find the electrical system grounding wire entering the panel somewhere. You can use a "bug" (little U shaped clamp with a nut) to make the connection between the grounding wire and the bonding wire. That connection will satisfy the requirement to make sure that the electrical ground system and the radio ground system are at the same potential (thus no shock hazard).
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Bob  AA4PB
Garrisonville, VA

KA1JNK

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Re: 12v battery and grounding
« Reply #12 on: December 09, 2020, 11:29:26 AM »

If I were in your situation, and I could get a #6 conductor from the shack to the electrical panel inside the house that's where I would run the bonding wire. You'll probably find the electrical system grounding wire entering the panel somewhere. You can use a "bug" (little U shaped clamp with a nut) to make the connection between the grounding wire and the bonding wire. That connection will satisfy the requirement to make sure that the electrical ground system and the radio ground system are at the same potential (thus no shock hazard).
I have a 'Ufer' ground that sticks out of my foundation, inside my house, by my panel. If I were to run the #6 wire as you suggest would I still plant a couple of rods outside my shack to ground my coax before entering the shack?
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AA4PB

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Re: 12v battery and grounding
« Reply #13 on: December 09, 2020, 11:50:29 AM »

That is a good idea but you also have to bond those rods to the #6 bonding wire. Otherwise you could have a shock hazard when disconnecting the coax from the radio.
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Bob  AA4PB
Garrisonville, VA

KA1JNK

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Re: 12v battery and grounding
« Reply #14 on: December 10, 2020, 03:47:09 PM »

OK, change of plans. I've decided to put my shack by the main panel and use the AC and grounding there.

Here is a picture of my proposed setup. Any recommendations? Do I need to run the #6 from the buss bar behind the table to the house ground as well?

Thanks for all of your help.
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