High Voltage 130-135V

Old 11-26-07, 05:16 PM
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High Voltage 130-135V

I have a mountain cabin in a small town that generally only sees use on the weekends. Today, several residents in the town indicated that they were getting voltage readings between 130-135V. Since that's high enough to damage equipment, they were advised by the POCO to unplug sensitive equipment. Later today, the POCO was able to fix the problem.

Although this is the first time I've heard about a high voltage problem throughout the town, some of the residents have said that the voltage fluctuates on the high side at times. (I'm surprised, because the town has about 3000 people and is a few miles wide by a half mile deep, with its own substation.) What can I do to protect my equipment, while minimizing any inconvenience to potential renters? Also, does the POCO have any liability for damaged equipment due to a voltage problem on their end?
Old 11-26-07, 05:32 PM
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typically, POCO is allowed to deliver up to 132 volts (120 + 10%). That is the max limit and up to that point should not actually cause harm. Most equipment per NEMA (national electrical manufacturers assoc) standards are to be designed to actually operate on nominal voltage+-10%.

as to POCO liability? possibly but can be hard to prove and make a successful claim.

There are a lot of variables that can change the possibility.


surge supressors that have a low let through voltage limit.

Line conditioners
Old 11-26-07, 05:32 PM
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Originally Posted by biking_brian View Post
Also, does the POCO have any liability for damaged equipment due to a voltage problem on their end?
No...(Or at least that is what they will tell you) .
However , You can leave that up to your home owners insurance to fight out with POCO, Usually with good results.
Old 11-27-07, 06:45 AM
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so, what do we think is "sensitive equipment"

I think the most sensitive will be halogen lighting (already runs high filament temps at 120volt), other incandescents, then followed by surge suppressors (which will destroy themselves over ~150volts). BTW, surge suppressors are NO help for sustained overvoltage issues, the only customer solution would be a line conditioner/autotransformer type. The only other thing you can do is buy 130v lamps. (long life bulbs)
Old 11-27-07, 07:58 AM
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A voltage regulating UPS on the computer, LDC TV and electronics are about as good as you can do. The good news with most electronics now is that many of them are designed with a world-wide market in mind and will operate just fine on 100-250V so long as the voltage is stable. Sustained high voltage is not as bad as sustained low voltage which can seriously damage motors. Probably the worst you will see is light bulbs burn out faster; motors should be largely unaffected by slightly overvoltage.

The POCO would probably only be liable for the voltage problems if you could prove it was negligence that caused it (very unlikely). Probably some tap changer or capacitor switch failed (due to poor maintenance but you could never prove it) or took a lightning strike which they will define as an "act of God" and disclaim any liability. If anything is damaged, you'll have much better luck with your home owners insurance.

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