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.
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.