Split phase voltage fluctuations

[Lewis Gardner <lgardner@xxxxxxxxxxxxxxxxxxxxxxxxxx>]

Yesterday the UPSes were complaining and the lights were flickering much
more than usual at my house. Since I live off the side of a side street
and it was cold, wet and icy I figured that the problem was external to
my house. Rather than call the utility on a wet weekend I decided to do
some troubleshooting.

Using a recording voltmeter I first checked between the phase
conductors. Over several hours (and many UPS events) the  fluctuations
was  9 VAC. Certainly not enough to cause lights to flicker to the
degree they were. Then I checked between each phase conductor and
neutral. One leg showed a  fluctuations of 23 VAC and the other 21 VAC.
The highest recorded voltage was 146 VAC and the lowest 108 VAC. There
were several 30 second intervals where the voltage stayed above 135 VAC.
Obviously there was a problem with the neutral.

A crew came this morning and replaced the overhead service line to the
pole. Squirrels (most likely) had chewed the neutral messenger wire down
to one aluminum and one steel wire!

I had guessed that a connection in the meter base was loose but after
checking that the service guy spotted roughness on the top of the
messenger wire. The bad places where located where phase wires were on
the bottom and a squirrel could sit and gnaw. These were easy to see
with a pair of binoculars. There was not a 6' section without damage.

After the overhead service was replaced a test of phase to neutral with
various loads shows  fluctuations of 5 VAC or less between 125 VAC and
120 VAC. Much better.

Something else to check if the UPSes beep...