It's used for routing test for insulation resistance & Electrial strength of switches, insulation material etc. as well as on line measurement of applied AC voltage, current & watt to load & other electrical parameters. The Flash unit consist of thick Acrylic sheet to prevent any leakage electric shock during H.v test .The compliance is check between line parts of pole & body so that no metal parts foil etc. should be present in moulded body.