Efficiency of Class III Surge Protection Devices against Lightning Surges

The power surges produced by lightning discharges affect the electrical network at residences and cause damages in home appliances. To avoid these damages, it is recommended to use Surge Protection Devices (SPD) in the power input of the appliances (SPD Class III). This article presents the current levels that the SPD Class III bypass at the entrance of the appliances. We show that the SPD can deflect 75% of the current that reaches it. We also show that SPD increase the voltage level supported by equipment in 2 kV or more and thus maintain the equipment's useful life. Cell phone chargers, laptop chargers and refrigerator power supply were submitted to a series of surges with different voltage levels to determine the number of surges that each equipment can withstand at a specific voltage. In all the studied equipment, SPD increased the number of supported surges.