For intermittent problems, a data logger or a meter that stores or records readings over extended periods can enable you to determine whether or not your suspicions are accurate. However, to correct the problem at its source, you need to understand why the neutral is overloaded. For that, you should have an instrument that performs harmonic analysis. One trait is common to almost all of the newer products, however. Although these instruments emphasize ease of use, impressive technology lies behind the panels.
Some units even publish power-quality data directly to Web pages on company intranets.
Instruments that have this capability appeal mainly to facilities engineers who must keep track of power quality at many locations. These packages make such power-related calculations as determining a waveform's harmonic content. In addition, if you sample more slowly, you can extend the captured interval's duration. When you're attempting to correlate a malfunction with an ac-line phenomenon, you usually don't have to reconstruct the line frequency's 40th harmonic. You may be able to sample more slowly until you determine when the problem arises.