The devices that prevent the damage effect of the high voltage waves occurring in the energy transmission lines as a result of high voltage line failures, lightning drops and breaker tripping or briefly the protection elements that discharge the overvoltage occurring in the energy transmission lines to the earth are called surge arresters. There are four types of surge protective device, Type – 1 (B), Type – 2 (C), Type – 3 (D) and Type – 1 + 2 (B + C), depending on their application. Lightning protection systems protect the facilities only against the physical effects of lightning. This does not mean that the electrical devices are fully protected. For electrical protection, surge arresters must be used in the facilities. The protection of the surge arrester (Type B) used in the main panels cannot be guaranteed in the secondary panels. Most of the overvoltage pulses are caused by internal overvoltage and C type surge arresters should be used in secondary panels against such voltages. In the main panel suitable for use in surge arresters, Iimp current is declared in the surge arrester suitable for use in secondary panels and sensitive device panels.