On Saturday, April 5, 2008, the electrocution of a fat rat in an electric station of Stockholm, Sweden caused a three-hour power outage in Stockholm's central train station, halting elevators and escalators. This was an early morning outage that led to some delays in train traffic and all nearby hotels and shops were also affected.
The rat had sneaked into a secondary substation and came into contact with some parts that caused it to short circuit. It must have been of really big size because there's a certain distance between the parts of the secondary substation it touched. This has rekindled the urgency of proper precautions to avoid such uninvited power outages and the Stockholm will now have to decontaminate the area where the rat met its fate.
In fact, this is a serious message to the whole world to take precautionary measures at their national girds and substations as the short circuiting of the pervading electric network can be susceptible even to the intruding animals and birds apart from the fact that strong winds of rainstorms, thunderstorms and dust storms are not only cause of short circuiting the electric transmission system due to falling limbs of trees on the electric lines during the storms. Power outages are also caused by isolated lightning strikes on the transmission girds as happened at Dayton, USA on Friday, April 4, 2008.
A huge blackout occurred in Los Angeles on September 13, 2005 after a worker mistakenly cut a wrong line, triggering a cascade of problems in the city's power grid. The largest blackout in North America's history occurred on August 14, 2003 when East Lake power plant of America was shut down unexpectedly on August 14, 2003, triggering a series of problems on its transmission line that triggered a cascade effect that caused the cross-border blackout.
Thus power outages can be caused by many things such as storms, wind, heat, trees, vehicles, earthquakes, animals, lightning, excavation digging and high power demand. During heat waves and other times of unusually high power demand, overburdened electric cables, transformers, and other electrical equipment can melt and fail. While the developed countries enjoy a highly uninterrupted supply of electric power all the time, many developing countries have acute power shortage as compared to the demand.