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Question: Grounding Wires and Animals

Jan 30th, 19:01

KN6SNH

Joined: Jan 25th, 16:09
Total Topics: 0
Total Posts: 0
Hi, I'm a new member and a new Ham.

I'm setting up my shack's grounding system and there was something I didn't consider. I'm in the process of attaching the ground inside to a ground bar and everything looks as I had planned.

Then...my wife says "how are you going to keep the animals from touching the bar or the wire so they don't get electrocuted?"

I said, hmmm, I don't know. I hadn't considered that.

My question Is the ground line and ground bar dangerous if touched? I guess it could be considering its purpose.

Thank you for any help.

David
KN6SNH
Feb 2nd, 23:06

K0WUQ

Joined: Dec 3rd 2012, 11:13
Total Topics: 0
Total Posts: 0
Well, David, I will give you a purely theoretical answer that SHOULD be correct. But, more seasoned hams can certainly argue.

If a ground bar is REALLY grounded, i.e. well attached to an 8ft long copper-clad rod driven fully into the ground, it will always be at "zero potential" relative to the earth around it - EVEN when there is RF current from equipment flowing through it. That "zero potential" is the very reason we have a ground running into our shack. So, even if a beloved barn cat pees on the ground wire while we're running 1000 watts, he shouldn't be harmed.

Electrocution always depends on being BETWEEN two points of different "potential" (which is just an old word for voltage). That's what makes current flow, and current is what zaps us or kills us. I used to work on color TV with picture tube voltages of 25,000 volts and enough oomph to definitely kill, but the old TV repairman's advice of "keep one hand in your pocket" was what I went by. I have been shocked many times over the years by up to 300 volts DC and am still here to tell you about it - but always because of the "one hand rule".

Some big AM broadcast stations have whole towers that carry RF energy at fantastic voltages, with a big blob of porcelain at the bottom to keep them insulated from ground. Anybody who needs to climb that tower gets up on a little wooden platform and then JUMPS over to the ladder on the tower and grabs hold, then starts his climb. When he makes it back down, he jumps from the ladder back to the platform. Thus, his body is never "across" the RF voltage difference (which is in the thousands of volts). This is even though the bottom of the antenna tower is supposed to be the "voltage node" of the RF standing wave in the 1/4-wave tower.

Life or death is in what two things you touch at the same time and the voltage between them. An animal on the ground touching a truly grounded wire should be in no danger at all.

Any other views / comments?

Larry K0WUQ
Feb 3rd, 21:27

KN6SNH

Joined: Jan 25th, 16:09
Total Topics: 0
Total Posts: 0
Larry, thank you for the very thoughtful answer. I will be interested if anyone else has something to add. I had no idea what I was getting myself into when deciding to start this hobby but it's getting my old brain moving again between studying the test materials and planning the Ham shack.
Feb 4th, 00:02

K0WUQ

Joined: Dec 3rd 2012, 11:13
Total Topics: 0
Total Posts: 0
David,

You're welcome to it.

Are you an ATM or is that just a heck of a camera? Telescope making is another old hobby of mine.

Larry K0WUQ

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