House Voltage... Does it really matter?

[fa35jsf]

So my house receives higher than normal voltage from the power company. Between 125-126 volts depending on which outlet you check and where it is on the property. That is over 250v on what should be 240v service.

So, does it really matter?
How does this happen?
Can it be adjusted? (of course assuming that would require the power company coming out to do something on their equipment)
Will this higher voltage cause damage to anything over time?

 

[Triple Jim]

It doesn't matter. I'm often around 125 here. In general, 10% voltage errors are no problem for any device. That would mean a range of about 108 to 132 volts, or 216 to 264 volts. But decide for yourself, of course.

 

[DieselAddict]

Yep, 10% plus or minus is a-ok.

 

[quickfarms]

In 1984 the NEC was changed so that the standard voltage used for load calculations was changed to 120 volts. (Again I don’t really understand why the change happened, just that it did.)

Today utilities are required to supply you with voltage that doesn’t vary from 120 volts by more than 5% either way. So that would mean your voltage should be between 114 and 126 volts.

 

[Triple Jim]

Back in the days of incandescent bulbs, a few percent high would shorten their life more that that few percent. In those days I probably would have talked to my power company if the voltage were consistently more than the plus 5% spec. If nothing were done about it, the alternative was to buy 130 volt bulbs, which although not really common, were available.

 

[Bill W]

My battery back up on my TV will start beeping when my genset drops to 117volts but not the one on my computer ( 2 different brands ). If I keep it at 119v or above everything is fine???

 

[Triple Jim]

UPSs have arbitrary alarm settings like that. Some are programmable to any voltage you like. I had one that occasionally beeped when on generator power, probably as things like the well pump started. That one has a menu system and I was able to adjust the low voltage alarm lower to make it quit beeping.

 

[csheath]

Mine measures 248 so that's where I set my generator.

 

[CMPPhil]

Hi All

Has anybody taken a look at their power on a scope to look at the shape of the wave as well how clean the power is? I've recently been looking at the power from the power from the utility as well as my Honda 3500 and my M5 military generator. Will post some pictures soon of the scope traces.

Cheers Phil

 

[rhurey]

Yes.

https://www.steelsoldiers.com/showthread.php?152641-Power-waveforms-amp-MEP-generators&highlight=

I haven't done much looking at unbalanced 120V loads and how well the unit handles those.

 

[Bighorn]

http://wattenburg.us/energyresearch.html

I used to listen to Dr. Bill Wattenburg back when he was on KGO.
One night he took to task Pacific Gas and Electric for their use of higher than necessary line voltages.
It caused quite a controversy.

Basically, in the article above, it states that scientific evidence suggests motors in home appliances run LESS efficiently at high voltages than they were built for.
So it was asked why PG&E ran line voltages well above standard.
Could there be a reason they would want less efficiency since they have an energy monopoly in the most highly populated state?
Anyhow, if anyone is interested, the link is above.

 

[rustystud]

http://wattenburg.us/energyresearch.html

I used to listen to Dr. Bill Wattenburg back when he was on KGO.
One night he took to task Pacific Gas and Electric for their use of higher than necessary line voltages.
It caused quite a controversy.

Basically, in the article above, it states that scientific evidence suggests motors in home appliances run LESS efficiently at high voltages than they were built for.
So it was asked why PG&E ran line voltages well above standard.
Could there be a reason they would want less efficiency since they have an energy monopoly in the most highly populated state?
Anyhow, if anyone is interested, the link is above.

You increase your power lines efficiency by increasing the voltage. That is why major power lines from Hydro power plants and such are in the thousands of volts. You experience less voltage loss the higher your voltage. More lose equals more money spent, so increase the voltage and increase the money !

That was one of the first lessons I learned when I took "Electrical Engineering" . I only took it for two years and never got my degree. I was already a "Master Mechanic" and just wanted the extra knowledge. As they say, I learned enough to be scary ! " Why yes I can fix your TV !!!! " . Just let me take it apart !

 

[pjwest03]

Also, if you want 120/240V for the last house on the line/street/road, you have to set the voltage high enough to account for the loses. The first house may indeed see 125V+ and the last house may be down at 117V. If you watch the voltage over the day, it will tend to be highest late night when most are sleeping, and lowest in the 4-8pm range when everyone comes home from work and turns all their crap on.

 

[CMPPhil]

Yes.

https://www.steelsoldiers.com/showthread.php?152641-Power-waveforms-amp-MEP-generators&highlight=

I haven't done much looking at unbalanced 120V loads and how well the unit handles those.

Hi
Thanks for sharing the link and the info it leads to. Will post the traces from my M5 generator, Honda and utility this weekend. To keep the threads focus will post scope traces to the other thread.

Thanks again your traces confirmed what I was seeing.

Cheers Phil