I think my household electricity is out of spec and causing me problems. I
have to replace lightbulbs frequently, and a power conditioner I have (to
protect some electronics in one room) shows unexpectedly high input voltage.
A digital VOM shows 123.0 to 124.8 volts in my house, compared to 118 and
120 in other locations in the city.
Is there anything I can do about this, or have an electrician do? Or should
I talk to the electric company?
Here in the US, IEEE ,,,, I think 519 says plus 5% to minus 10 % except for
short periods of time.
Nominal is 120, so your using the extreme your at 104%. The utility will
basically ignore you.
Your digital vom is RMS? if not it is averaging so your peaks could be
higher. Can you do a min- max on the circuits? Even with my Fluke 87
calibrated yearly, I would not bother the utility.
Bite the bullet and by a surge protector for your service. Install it and
thank god your not in a low voltage condition. Check to see that your
electrical connections are tight especially the ground and be glad your not
in a low voltage condition.
You could buy a ups that regulates the incoming voltage, for a grand for the
sensitive electronics. I would not bother.
You're within 5% of the 120V nominal so I wouldn't worry nor expect the
power co. to worry (but you can try). If you are running *over* 125V
consistantly you could call the utility and see if they could retap the
local transformer for a slightly lower voltage. For equipment design the
expected normal range is assumed to be +10/-15% or 132 to 104V for a 120 V
nominal service (including minor brownouts, voltage drops in wiring *after*
the service entrance, things that go bump in the night, etc.). Much modern
equipment using switching power supplies should tolerate either 87-132V or
190-264V input (if dual voltage) or 87-264V if universal input (so as to be
useable in Japan at 100V, N.A. and parts of S.A. at 120V, Europe, etc. at
220, 230 or 240, plus parts of S.A. at 127V)
If you have equipment that cannot tolerate 125V you could have an
electrician install a boost-buck transformer to make a slight reduction in
voltage. The power conditioner should tolerate the higher voltage,and
presumabily reduce it slightly in addition to keeping it stable and
reasonable dropout/spike free. For incandesent lighting (I suspect your
biggest problem), the best solution may be to buy 125-130V (128V design)
bulbs (or just "Long Life" labeled bulbs, basicly the same thing but for
labeling) instead of 120V bulbs, for, as you notice, a 120V lamp at 124V has
about 2/3 rds the life, is about 10% brighter and uses about 5% more
power -- a tradeoff of efficency for life.
Here's a lamp performance calculator: http://www.deepsea.com/lampcalc.html
I would say, "Thank you God." Mine reads as low as 118.5,
depending on the meter, and as high as 124.3; none of those
meters read true rms. The power company says it should read
above 120 most of the time.
By the way, I don't have light bulbs burn out frequently and
nothing has ever hurt my computer or other electronic
equipments, audio, TV, etc. I think you have some other
problem, especially if you experience unusually high input
voltages. 125 is not a high voltage.
123-124.8 is well within spec. Besides, unless you have a properly
calibrated DVM, I don't trust them on AC.
This shouldn't be the problem with your lightbulbs. And I expect that
a power conditioner wouldn't consider 124.8V "abnormally high".
One thing you consider is whether the lightbulbs that are going bad are
subject to a lot of vibration (ie: ones on bottoms of stair cases ;-),
and it's worthwhile trying a different bulb manufacturer.
There's one thing you should try with your DVM however. Open up your
main panel, and test the voltage on two adjacent breakers. It should
be 240V (+- 5%) between the two, and when measured from each breaker
to neutral buss bar, both voltages should be the same.
If they're more than a volt or two different, then you have a neutral
problem. This would explain the bulb failures, expecially if you have
flickering (both down and _up_) on multiple circuits when large 120V loads
If you do see a difference, call your power company and say "loose neutral".
They'll be there fast...
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
As others have noted, I don't think it is the delivered voltage.
Other possible problems:
Cheap fixtures (results in poor connections)
Floating neutrals (causes changing voltage some high some low)
Too high wattage lamps for the fixture
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