in my apartment I noticed recently that my bedside clock and oven clock, which are both powered from the wall, were about 15 minutes ahead. I changed them back to the correct time, but the next day they were already a few minutes ahead. I have also had a few WiFi routers suddenly stop working over the past few months.
Could this indicate that something is wrong with the electricity in my apartment? If so, what can I do to check it myself before calling an electrician?
Thanks!
Update: I contacted the power company and it turns out that the mains frequency was, in fact, higher than normal. There was a water main that burst (and caved in part of the street) in my neighborhood and the city feared that it would damage the underground powerlines, so they turned on the emergency power generators to ensure that nobody would lose power, even temporarily, while they fixed the water pipes. They said that they had to increase the mains frequency in order to prevent damaging the generators. They ran the generators for about a week, but service is back to normal now. My clocks are functioning normally again and it turns out that my router issue was unrelated. Thanks for everyone's input!
Best Answer
These types of clocks usually keep time by counting mains cycles rather than using any sort of internal timer chip.
So, if your mains frequency is too high, they will run fast. The fact that two clocks are running similarly fast is another clue that this may be the case.
It is conceivable that too high a frequency is upsetting your routers. If you have a technical manual for them that might give a frequency tolerance figure.
To check the mains frequency yourself, you'll need an oscilloscope. Pretty much any oscilloscope will do.
There is a quality standard for the frequency of the mains supply. You can always challenge your electricity supplier and get them to measure it.
If your frequency is different from other nearby homes, then something is interfering.
You could try an online tester such as this one but I can't vouch for their accuracy. It might at least give you an initial guide but it seems black magic for a webapp to tell you your mains frequency.