I could use the advice of an electrician. I’ve been monitoring the voltage in my (recently purchased) house for the last few weeks. It’s been hovering around 123-124V on either leg, dropping to about 118-120V at times. The circuits I’m monitoring, one on each leg, have no load on them. I realize that what I’m reading may be within spec for the utility, but is it worth it to try to get them to retap the transformer, or should I just not worry about it? And, in case it matters, it looks like there are 4 houses on the transformer (underground service), with my meter being the closest at about 60′ (it’s in my front yard at the property corner). All houses on this street are 10 years old and have 200A service.
Be seeing you…
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Definitely don't worry about it. 118 - 124 is fine. The midpoint of your range is 121. It doesn't get much better than that.
-- J.S.
Anything less than 125v wouldn't cause me any concern. Better a little high than low. Your motor loads don't like low. One thing to watch for, and a real problem, would be if one leg goes high while the other leg goes low. As if voltage from one was being transferred to the other. Lights going double bright are a common symptom of this. If this happens don't hesitate to call the power company and have them load check the lines. They will advise you if they can't help and need an electrician.
Your power company would also be a good starting point for general voltage questions. Some will tell you over the phone how they define high and low voltage conditions. Most will quickly send out a trouble shooter for issues and will do so for free.
Also make sure your meter reads correctely. It may not be the actual line voltage, but a non-accurate meter. See if you can compare to someone else's calibrated meter.
Ditto on this. I had the power company come out and check the transformer after measusing voltage readings of 135+v per leg, only to find out that meter was going.
> One thing to watch for, and a real problem, would be if one leg goes high while the other leg goes low. As if voltage from one was being transferred to the other.
This is a symptom of resistance in the neutral, or in the worst case, an open neutral. It can happen either on the utility's side of things, or on yours. It follows from Murphy's law that when you lose a neutral, all the most expensive electronic stuff will be on the side that goes high.
-- J.S.
That happened at my last house, but without damage. Neutral impedance slowly crept up until the "brightening" of some lights and dimming of others on motor startup prompted me to check with a voltmeter. Voltage was swinging +/- 20V (or more), depending upon which leg I was looking at when turning on a space heater. It was swinging around pretty good with regular household loads going on and off at the other three houses on the transformer. The worst, as expected, was during the day. The utility cut and reconnected the outdoor splices and the problem went away.
And speaking of the utility, I'm not going to bother calling about the 123+V issue unless I start burning out light bulbs too quickly. Thanks for the advice. And to Junk Hound, my digital meter is only so-so, and so are the other two analog units I checked with, but they all said the same thing at the same time. I'm not going to lose sleep over it. Thanks to you to. And anyone else I missed (unfortunately, I can't review all the other posts while writing without losing what I've written).
Edit: And you too, 4LORN1.
Be seeing you...
Edited 7/2/2002 7:16:00 PM ET by TDKPE
Always happens that way. The $7000 computer will fry to protect a $.10 fuse.
On suspected neutral problems I used to recommend getting an electrician ASAP but I have seen at least one case where the electrician missed it and equipment was damaged. That combined with the fact that the majority of these cases seem to be utility company problems has caused me to change my general recommendation. Now I say to call the power company first. They tend to respond in a timely manner and when it is not on their end, assuming it is a major fault, they yank the power. Not real convenient for the HO but it is safe.