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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