On May 11, 2013, at 7:51 41AM, "K1TTT" <K1TTT@ARRL.NET> wrote:
Consider this example... my neighbor had a broken ground in the wire
overhead from the transformer to his entrance panel. There are ground
rods
at the pole and at his entrance as required. When a big load on one side
of
the line started, like a refrigerator, that leg browned out but the other
leg of the 220 would get up to about 200v and blow out stuff on that
circuit
due to the overvoltage. Obviously there wasn't enough return current
through the ground, even over that relatively short distance, to keep the
supply balanced.
No... Your neighbor had a broken or high resistance NEUTRAL! A broken
"ground" will not cause this! This is a common phenomenon. When the air 120
volt compressor starts in my shop/garage, the lights (read voltage goes up)
get brighter on the other phase when the compressor starts.
That's because the neutral from the street pad mounted transformer is
smaller than the 120 volt legs. This voltage drop in the neutral, un
balances the voltage. I'm 175 feet from my transformer. It's very common to
see this even with short length conductors from the distribution transformer
to the service entrance.
73
Jim W7RY
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