ABB OVR type 1 and type 1+2 are designed to discharge high current surges without any destruction of the installation. This surge protective device is chararcterized by its capacity to withstand impulse current with 10/350 µs wave form which simulate direct impact coming from a natural lightning current. Type 1 and Type 1+2 SPDs are placed at the entrance point of the installation, in the main distribution board for a global protection of this installation. Main benefits include The impulse current of 25kA per pole (10/350 µs wave) satisfies all requirements for overvoltage surge protection; The early creation of the electric arc by its electronic ignition device reduces the protection level Up to an optimum value of 2,5kV & OVR T1 SPDs contain a dedicated arc chamber for extinguishing the electrical arc following the discharge, they can open short circuits up to 50kA without using back up protection. Main features include limp 25kA and 12.5kA; 3 types of follow current (If) 50, 15 and 7kA & Spark gap and varistor technology.