RMS values cause a lot of confusion and many engineers do not fully understand their importance as a unit of energy. Problems arise when an inductive or capacitive load puts the current and voltage out of phase. This is why conventional fluorescent light fittings include a capacitor to correct the offset created by the ballast or choke. From a metering point of view, suppliers have the right to surcharge an account when the AVERAGE power factor is below 0.9 Many problems arise when large motors have to limit the inrush current on startup by a combination of sliprings in series with the rotor during startup. along with removing the load. On refrigeration, this is achieved by a solenoid valve opening to bypass the compressors. suction and discharge lines. In the theatre, our total sensible and latent load was between 48 and 96 tons in summer. The problem was that electricity supply companies tended to carry out their inspections in winter, when their was no load, in addition to not averaging it over our 14 hour working day. When I corrected their figures, they just gave up and accepted mine.