Fluctuation in line voltage can be caused by loose or corroded lines in either the house or the power lines, according to Northpower. It is also caused by insufficient wiring installation and even lightning strikes on or in the vicinity of power lines.
Additionally, existing electrical infrastructure commonly deals with increasing electrical demands, which it is not always able to accommodate. Poor power generation and distribution is the result. Symptoms of voltage fluctuation include flickering or dimming lights, computer crashes, motor tripping, cooking problems, equipment stalling and even electrical shocks. The lifespan of light bulbs is also a common indicator, as light bulbs do not last as long under poor power distribution.