Harmonic currents and voltages appearing on a building's AC 7 power distribution system are a form of power quality (PQ) problems. In some cases these problems may be so slight as to be non-existent from a practical standpoint and so may be dismissed. Remember, just because modem test equipment such as a harmonic analyzer or power line analyzer (PLA) can detect and report on the harmonic currents and voltages for the circuit being examined, the presence of these conditions does not automatically mean trouble.