If a bolt of lightning strikes a power line or a telephone line connected to your home, there are chances for your home appliances to experience a power surge. This might damage electronics, blow out circuits, and melt the plastic around the wires and outlets.
Apart from lightning strikes, power surges occur from within your home more frequently than you think. Every time when the large appliances such as refrigerators or washing machines are turned on or off, power surges occur because of the change in load, thus damaging your appliances by slowly degrading the integrity of the wires and processors within them. It even takes years for the effects of these surges to be seen.
These electrical surges can be protected by installing a surge protector in your home and by plugging your appliances into it. When a power surge is detected, the surge protector diverts the surge to the ground, thus preventing it from reaching the connected devices. This prevents your electrical appliances from the damages caused by power surges.
Also, having a voltage regulator on board along with your home appliances also protects your devices from frequent power fluctuations, by adjusting the provided voltage and maintaining it at the correct levels.