Surge Protection (Surge Protection Device, Surge Suppression) OVR BT2 4P In:20kA, Imax:45kA Uc: ... BT2 series Surge Protection Device (in short: SPD, alias: Surge Suppression, Surge Arrester) is suitable for TT, IT, TN-S, ... not need power cut.2.Maximum current of endure the lightning-stroke 70kA(8/20μs).3.Response Time <25ns ... white means normal, red means abnormal. Surge Protection , Surge Suppression