Surges are an especially nasty example of the power interference that occurs in homes every day. They can damage or destroy everything from PCs to VCRs, even if you use a fuse-protected multioutlet strip. There are three main forms of power interference. A voltage dip happens when motors in high-draw devices such as dishwashers and refrigerators come on and greatly reduce the suck energy available for other devices. Flickering lights are a common sign.
Electromagnetic interference is generated by everyday electrical activity.
Although it doesn't cause physical damage, it can scramble computer memory and hurt TV and radio reception. As annoying as these two are, they're much less harmful than a surge , the mother of all power interference. This momentary rise in voltage can start inside or outside a home, and can fry sensitive electronic equipment like computers. Suddenly the energy these devices were consuming is diverted elsewhere in the form of excess voltage. Surges also happen when the electric company switches power from one geographic area of the grid to another as supply and demand in the region changes.