About 2 months ago my apc ups es-500 started switching over to battery for a couple of seconds several times a day. Sometimes several times an hour. I checked the logs and it said that it switched to battery because the frequency was out of range. I thought the ups was maybe going bad or something because seriously, how could the AC frequency go out of range? Anyway here it is 2 months later and I am worried that the constant switching is going to kill the battery to something. So since the log said the frequency was going out of range I decided to plug my multi meter into an outlet near by. Low an behold, the ups eventually switched to battery for about 4 seconds and during that time the multi meter when from reading 60hz to dancing around 150-250+hz for about 2 seconds! What the heck is this?! How in the world would I begin to trouble shoot this in my house?? Or what could I buy to filter/correct this problem?
I'm not 100% on all this but i think electricity suppliers have to supply power within voltage, frequency & noise specifications to each building they supply, so this should be their problem, just like if you had a noisy telephone line. I'd first be unplugging everything in your home just to make sure it isn't something you have causing the interference, and just have the multimeter plugged in, nothing else. If the problem is still there, call the electricity company up and report the fault! If by some freaky chance it was say your fridge causing that much trouble, then you'd call the fridge repairman but this sounds like a supply issue. If the interference was being casued from a neighbour, then i think the electricity company would have to enforce the neighbour to remove or repair the non-complaint device so that the electricity company is able to supply power to their customers power within spec. It should all be pretty similar to telephone line providers. I also think that most if not all companies will charge you for the service call if they come out and find out that you have something that is causing the interference or if your ups was just faulty for example, so ask them for all the terms and conditions before getting them to send out someone to your place or to check your line, etc.
Other than the possibility of bad wiring (and this seems like a very unlikely result for wiring problems), the problem is probably at the power supplier's end. As you've tested with the multimeter it's definitely not just the UPS, so I'd call the power company and at least see if they have anything to say on the matter. Interference from devices could manifest itself in quite a number of ways, but a AC frequency jump seems fairly unlikely.
ugh. Well all of this is just so random and sporadic that I can't even trouble shoot. Like 2 days ago it didn't do it at all and I hadn't changed anything. It appears to have stopped happening during the day but it is really bad in the early morning and late evening. Like last night, for a good 20 seconds every light in the house was flickering wildly and everything plugged into the wall was making a nice loud buzzing noise.
You should check another socket in the same room and then one socket in 2 other rooms to see if it is a localized problem. If it is then that would help narrow down the causes. Also I could see things like a ridex+ or one of those network over power line things causing this pretty easily. If you have a nice HDTV and a good sound system you should notice better quality after you fix this glitch, assuming that it is on every socket...
To the OP- You might have already fixed this as I know it's been sometime, but just in case, here's my shot. I'm an EMC engineer and essentially what you're talking about is a conducted emissions problem. The power in your wall is still 60 Hz, but something is occasionally throwing out so much 150-250 Hz noise that it's seriously messing everything up. And other people are correct, the power company is mandated by federal law to provide power in the 60.05 to 59.95 Hz range otherwise they face massive fines. However with that said it's probably not technically the power company's fault. This is most likely being caused by an incorrectly functioning appliance somewhere in your house (I'd say > 90% chance) or (< 10% chance) something with your local transformer outside your house. So the steps I would do to try to correct it are: 1-Unplug anything you consider valuable or expensive immediately. Those sort of frequency swings can cause severe damage to most devices. At the very least put valuable/expensive items on UPSes. The worst case scenario is the power swings kill the UPS and not your $1,000 TV. 2- Call the power company and explain what's going on just in case and have them check everything from the transformer to the AC feed coming into your wall. 3- This one could be tricky for you, especially if you don't live alone. Try unplugging everything in the house except said UPS. By everything I mean your TVs, your non battery powered clocks, your fridge, your oven etc. The easiest approach is to kill the breakers to everything but that outlet in that room. Now give it 24-48 hours and see if it happens again. If it does, you know the problem must be in the room (maybe even the UPS itself) or with your breaker box. If not, do a phased reinitialization of the parts in your house, i.e. kitchen power first. Wait a day till it's all clear, then another room, etc. It sucks but that's the only real way to figure out what's going on short of using a spectrum analyzer. Either way I want to emphasize that this isn't a small problem- it will lead to premature death of electrical components until it's either fixed or goes away. Since you said it's sporadic my bet is that it's an automated appliance in your house generating the noise (i.e. ice cube maker, sub pump in your basement, garage opener, etc...) Once you find whatever it is you can either throw it away or install a line filter on that item that will filter out non-60 Hz signals. Just make sure the filter is bidirectional (i.e. filters power both to and from the place you attach it). Good luck!
I think it might have been a bad meter out on the pole. I couple of people from the local power company came into my yard about a week ago to replace the meter. They said that it wasn't reading right. Since then I have not had a problem. But ironically I hadn't had a problem since a couple of days prior to that so...
I have been meaning to update this post for awhile now.. Basically the night of the superbowl in January, the lights started flickering and buzzing again. This time alittle worse than before. Then the next thing we knew was 4ft flames going up the telephone pole outside and we were plunged into 2 days of darkness....
