The ASCO Model 480 Surge Protective Device is our largest, highest kA (SPD). The Model 480 utilizes two separate, dual redundant replaceable modules that work in parallel. It features large block, 50kA thermally protected MOV’s with surge current levels of 400kA, 600kA, 800kA and 1000kA per phase. This unit is for 'Mission-Critical' environments.