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Split phase voltage fluctuations

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...

Reply to
Lewis Gardner
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Reply to
BruceR

Sounds Like Someplace to Hunt Squirls

Reply to
George Ross

"Underground aerials"?? ;-)

Reply to
Frank Olson

You can have problems with underground service as well, especially if you live in colder regions. Where the cable rises above the frost line it can be damaged over time. There's more of an affect on communications cable but problems with AC power are not unheard of.

Reply to
Robert L Bass

in colder regions. Where the cable rises above the

communications cable but problems with AC power are not

Yep.

Around here all the first generation underground suburban residential services (circa 1970) had to be replaced. Insulation failure due to rodents or deterioration caused all sorts of wild problems.

I am not totally convinced that underground is the panacea that it is made out to be. Failures occur in both systems and underground takes much longer to fix. Of course underground failures don't usually happen all at once like a big wind or ice storm can cause. A few major earthquakes could change that...

Reply to
Lewis Gardner

Lewis Gardner wrote in news:45bd3129$1 snipped-for-privacy@news.iglou.com:

I lived in Southern California for many years and experienced many earthquakes, including the Northridge earthquake.

Aboveground lines fail in some earthquakes. Aboveground substation equipment falls over and causes failures. Maybe there have been underground failures due to earthquakes but I am not aware of any.

In the Northridge earthquake, underground natural gas pipes and water pipes and sewer pipes broke or sprang leaks. These pipes tend to be rigid and brittle, breaking when flexed sufficiently. Electrical conduit tends to be more forgiving. Even if it cracked, the wires inside would still be usable.

In the Northridge earthquake, I lost water service because the concrete meter vault sliced through the service line to my house. I lost electrical power because the substations were knocked out. Once the substations were repaired, power was restored. The underground wires in my neighborhood were untouched. The underground transformer in a vault 50 feet from my house was untouched.

Ice and wind take out overhead power lines directly and by bringing down tree limbs on the power lines. Ice and wind can't touch underground lines.

I will admit that the underground transformer was at a higher elevation than my house, so that heavy rains would fill the vault until water ran through the conduits that ran from the transformer and flooded the wall of my house behind the meter panel. Once the power company properly plugged the conduit, I didn't have that problem anymore.

I will take underground reliability over above ground anytime. The scenery looks a lot better too.

Reply to
Ian Shef

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