This is a slip shod method for checking ground fault failure in street lighting and ignores physics. There are devices called electroscopes and these are widely used in any environment that uses explosive gases. They determine static charge by sensing the efield. But the static efield varies with relative humidity. The average efield value of the efield of AC is zero. We have to measure the instantaneous value or the Root Mean Square value and adjust for distance as the efield varies with distance and relative humidity.There is no AC electroscope that can do this. There are good EMF devices that can measure EMF fields but the overpowering EMF signal would come from arcing because of its wide wave band. Great advances have been made in signal analysis and I can not rule That useful information can be scanned. However, this can not in anyway replace direct contact inspection. By the way while the electroscope can sense voltage directly the multimeter has to do a measurement indirectly. That is why the old Simpson meters loaded the circuit. Solid state devices such as the FET load also but to an insignificant degree.