White Outs are officially known as Voltage Swells and are a long term (either defined as greater than 1 minute or 3 minutes) power increase, and are so called as your normally white glowing incadecent bulb now glows even brighter!.

During a white out equipment may be damaged as more power may be consumed than intended, suppression devices may activate, fuses may blow and overheating may occur.

Whiteouts can be caused by a number of factors, including:

• Removal of Heavy Loads, raising the mains voltage
The mains voltage may be raised by the utility to ensure that the mains voltage is in tolerance when heavy loads are operating, for example on an industrial estate. When these loads are not operating it can cause the mains voltage to rise.
• Times of Low Demand

The normal parameters for defining a voltage swell is that the voltage is greater than 110% of the nominal and less than 180%.