Atmospheric events and on-off surges in the system cause formation of extreme voltages in electricity networks. ELOPAR surge arrestors are designed to protect distribution transformers, engines, work machines and medium voltage cables against extreme voltages in the best way. Elopar Metal Oxide Surge Arrestors; - have low protection level- High energy input capacity - High protection distance- Stable characteristics - are resistant to aging- Resistant to contamination - have porcelain body- Maintenance-free - safely installed- easy to use - Creeping distance is over 25 mm/kV- High support resistance Structure and Mode of Operation; Metal oxide surge arrestors do not contain gaps but contain metal oxide blocks that are placed one on another in a porcelain body. These blocks have variable resistance characteristics. In other words, they become conductive as the voltage rises. In case of temporary over voltage, current flows over surge arrestor so that such devices or cables are protected. These surge arrestors not only have a very good mechanical strength, but also have very good dielectrically smoothness in all surfaces. Furthermore, they have high resistance against contamination arising from atmospheric conditions under the heaviest operating conditions. ELOPAR Porcelain Body Surge Arrestors are manufactured according to TS EN 60099-4 (IEC 60099-4) standard in order to perform this task in the best way. Type tests have been performed at ICMET CRAIOVA High Power Laboratory and it has passed from all tests successfully. - Surge arrestors must be as close as possible to the device to be protected. - Surge Arrestor grounding must be the same with the system grounding.