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

[Charles Plunk]

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