Surge protectors are devices used to protect the electrical network, e.g. during strong lightning discharges. A lightning strike in installations, especially those with a large area, can damage not only the network itself, but also the equipment connected to it. The phase conductors and the neutral conductor are connected to the surge protector. In the event of a failure or a lightning strike, a current flows through the device, the value of which depends on the type of arrester. Its main task is to transfer the force resulting from the atmospheric discharge (or other source) to the grounding and thus protect the electrical installation against a serious failure. There are several types of surge protectors. Marked with the letter A, they are used for low voltage installations. Type B devices are installed to handle a voltage of 100 kV. Type C surge arresters are installed in facilities that are particularly exposed to lightning strikes. There are also D-type models that protect the remaining elements of the installation.