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Re: [RFI] Crepe Myrtle growing into power pole RFI Why?

To: K9MA <k9ma@sdellington.us>
Subject: Re: [RFI] Crepe Myrtle growing into power pole RFI Why?
From: Charles Plunk <af4o@twc.com>
Date: Mon, 24 May 2021 14:43:19 -0500
List-post: <mailto:rfi@contesting.com>
Thanks Scott. I sometimes think if they would use a good pressure washer and hose these things down real well occasionally it would solve a lot of these issues. At any rate, I guess i should not wonder why and just be happy I am finding them.

73

Chuck
W4NBO

On 5/24/21 2:24 PM, K9MA wrote:
Any two conductors anywhere near HV line can cause noise if they are not either 
well insulated from each other or securely bonded together. The field from the 
HV wires induces voltage in the conductor, which can cause an arc. In my 
experience, this is by far the most common cause of power line noise.

73,
Scott K9MA

----------

Scott Ellington

  --- via iPad

On May 24, 2021, at 2:13 PM, Charles Plunk <af4o@twc.com> wrote:

If you have been following my latest saga, I have a 3 phase pole at the corner 
of my back yard and another (both wood) in the front yard topped with 3x 7.2kv lines. 
Weeks ago I located an arc on the back pole through the usually methods and finally 
seeing it with binoculars in the dark. Power co fixed, it was the ground wire stapled 
to the pole to close to a bolt which mounts the fused disconnect. They simply moved 
the wire away and re-stapled. It is gone.

I had a 2nd arc on that pole but on the opposite side. It has all but 
disappeared on its own with higher humidity. I suspect it will return in the 
fall but ultrasonic tended to site on another part of the same ground wire.

Fast forward to 2 days ago, I begin to hear another strong arc. But this one is 
on the front yard pole. There is a crepe myrtle (~20-25' high) that has begun 
to grow around the pole but nowhere near the top 3 phase. Using my ultrasonic I 
heard it best lower on the pole where the crepe myrtle is around and probably 
touching the ground wire.

My question is, why is a wire at ground potential arcing to hardware insulated 
from the 7.2kv or to a crepe myrtle on either pole? Those ground wires go all 
the way to ground stapled to the pole uninsulated where anyone can touch them. 
I am glad to locate these rfi sources but trying to wrap my head around why?

73

Chuck

W4NBO

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