What is normal for electric line voltage?

[Windy in Kansas]

I have had my Kill-a-watt meter in use the past two weeks and line voltage has been as high as 122+ to as low as 115+. I have been figuring we are due for a brownout but so far none has arrived. The temperature was 103º today and it is usually at the hottest time of day when the voltage is lowest. Many businesses closed today so it didn't dip below 117+ that I saw.

I have also noticed that cycles per second are almost always 59.9. Does that make analog clocks slow over the period of a year?

[deaconjim]

Voltage will rise and fall depending on the load on the system, as will the frequency. It is an inherant part of electrical generation and should not cause a problem in the range you are describing.

[Windy in Kansas]

Thanks. I've never seen the frequency change but the line voltage had me worried. I don't have anything large that it would affect I don't think, but my neighbor has a large pool filter pump that I figured it might.

[deaconjim]

Originally Posted by Windy in Kansas

Thanks. I've never seen the frequency change but the line voltage had me worried. I don't have anything large that it would affect I don't think, but my neighbor has a large pool filter pump that I figured it might.

It's not necessarily your loads or your neighbors' that will cause it. An electric generator is designed to have a certain amount of voltage droop as load is applied. This allows load sharing between two or more generators. The same applies to the speed of the generator, which accounts for the frequency changes. As load on the entire system changes, you will see the voltage and speed change accordingly.

To answer your previous question about clocks, the change in frequency might cause some clocks to be less than perfectly accurate, but the average frequency over the course of the day should even it out somewhat. Still, you might have to reset your clock once a month or so to keep it on time.

[cfabe]

115-122 is well within normal range. Voltage will vary depending on grid conditions. Plus, different power companies can set a different norminal or target voltage for their systems. Most appliances are designed to operate normally on 10% over or under voltage, so you do not need to worry until you are below 105v or above 132 or so. Many items will continue to work normally well outside those voltage ranges, so it's something you really don't need to worry about until there is a suspected problem.

If you do suspect a voltage problem on a specific appliance in your home remember you need to be testing the voltage at the appliance, there can be significant voltage drop in your home (up to 5% per code, I believe) so the voltage can be different in different areas of your home as well.

Old analog clocks were synchronous to AC frequency and would be influenced by line frequency. But, I would guess that your meter you are using is not perfectly accurate, from what I have seen frequency is always very very close to 60hz. Any newer (newer than like 1960s) clock will have an analog face but a quartz or other digital type movement which means it will not be influenced. As a general rule, if the second hand "ticks" it won't be influenced, if the hand moves continuously it may be affected.

[Windy in Kansas]

Thanks for the replies. I'll not worry about it at all.

The transformer that provides electricity to both houses doesn't look the best. There is some oil streaking down the side of it which is never enough to coat the side nor reach the bottom to where it could drip. If it did I would call asking about PCBs.

Again, thanks.