A surge arrester, also known as a surge suppressor, is a device designed to protect electrical equipment and systems from voltage surges or spikes. Voltage surges can occur due to lightning strikes, power grid fluctuations, or switching operations. These surges can cause significant damage to sensitive electronic equipment, such as computers, televisions, and other devices.

Surge arresters work by diverting the excess voltage to the ground, preventing it from reaching and damaging the equipment. They typically consist of a metal oxide varistor (MOV) or gas discharge tube (GDT) that is connected between the equipment and the power source. When the voltage exceeds a certain threshold, the surge arrester conducts the excess energy to the ground, protecting the equipment.

Surge arresters are commonly used in residential, commercial, and industrial applications to protect against voltage surges. They are often built into power strips, electrical outlets, and other devices to provide additional protection for connected equipment.