--- On Tue, 9/1/09, Jim Brown <[email protected]> wrote:
The "coil" at the base of the pole sounds like lazy
electricians to me.
Nope, it's SOP in the utility business. And no end of trouble in the RFI
"business".
My rural electric co-op uses aluminum wire for the above-ground part of the
grounding system, either for cost, copper theft, or both reasons.
They also love staples and drive them at too frequent intervals up the pole to
secure the ground wire. Unfortunately, a green pole shrinks considerably in
the 6% RH typical here in the summer and the ground wire then arcs to the loose
staple. So the fix is to drive them deeper. I've then seen the wire cut when
the pole expands again when the RH increases. This nearly undetectable break
then arcs and generates lots of intermittent noise.
The same thing happens at the crimp they use to connect the aluminum to the
copper; that's a physically weak point that can break and cause the same
trouble.
This used to be a much worse problem before they replaced thousands of epoxy
insulators that crazed in the Arizona sunshine and had 100's of mA of leakage
current; a lot of it flowing in these ground wires. They actually had some
insulators catch fire from the heating.
Regards,
Wes N7WS
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