What is the voltage at your receptacle?

There are two standards for utility voltage. One is plus or minus 5 percent (114 to 126 volts RMS) which is "normal" and, in most cases, the utility is not obligated to correct or be liable for damgage to your electronics if the voltage falls within this range. The second range is 91.7% to 105.8% (110 to 127 volts) which is considered "acceptable" and the local gubment regs will have a say as to whether this is also litigation-free. Both are ANSI standards, and are recommended; not written in stone.

Is 124 volts too much? Not really. Most electronics are designed and built with the knowledge that voltage varies. Typical circuit devices, and more importantly insulators, are rated for 600 volt withstand. Also, RMS voltage is an average of sorts. In simple terms it means 70 pecent of the peak voltage. So the wall voltage of 120 volts, which is RMS, is actually 170 volts at peak.

But the other factor to consider is that the power to your house could be 120/240 on the nose and you have a problem at the service panel and ground which may cause one leg to read higher than the other. Your electrician should have checked that in addition to the outlets.

The voltage in my neighborhood (Bethesda, MD) is quite consistent, I typically see 117-120 volts all the time. This is based upon the display on my TrippLite UPS that is used to provide backup power to my main computer system. I have seen it dip as low as 116V and go as high as 121V, but only for the briefest of moments.

-RW-

I live in a rural area, there is a tranformer quite near to my house.
On a dedicated circuit, I have a Furman PL Pro-D power protector, which has a digital voltmeter built in.
I was constantly seeing high voltages displayed on that meter. 126v not unusual, and often 129-130v. Of course the Furman cuts out at overvoltage. It was happening frequently - sometimes every night. In the middle of watching TV, or a DVD, or listening to music - very annoying.
I called the power company, and they pretty much just shrugged. Maybe it could be fixed, they said. But I have an electric pottery kiln, and the high voltage is an advantage (cuts firing time) so I let it go.
I got a PS Audio power regenerator, and now my voltage is steady as a rock, and right where I need it.

124 volts +/- ,2 volts.

The two legs at my breaker box read 119.8 volts and 121.7 volts.

I have all my stereo dedicated runs connected to the 121.7 phase and noisy appliances such as refrigerator, TV, and bathroom outlet used for hair drier are all on the 119.8 V side.