Power Problems usually show up as computers resetting or giving error
messages about data Loss. Flickering Lights and appliances that regularly fail are typical signs of Power Quality Issues.

DataBase Errors or corruption are another mark of Electrical Problems on Site. The Graphs above show, Left, a typical problematic site with huge fluctuations and glitches during the day. The Right Graph shows the same site at the moment when the fault was corrected, which appears as a vertical shift followed by a smooth horizintal line.
The problem in this case was caused by the Street Transformer being overloaded, and had affected the site for a decade or more.

Problems like these can be fixed for several hundreds of dollars usually, but a good APC UPS is still required to keep your servers going properly.