These type-3 arresters are used for universal mounting in installation boxes, cable ducts, under floor or directly in the terminal. Installation is possible in stitch or through cables. Side straps on the device allow an easy mounting. The flexible conductors with ferrules or rigid cables up to 2.5mm ² can be connected in case of the spring mounts. Blocktrab can be used worldwide in grounded, isolated 230 V networks. Insulation measurement up to 500 V is possible without removing Blocktrab. Circuit is thermally controlled. With overstress or defect, an audible warning informs the user. In these cases, the internal protection circuit is disconnected. This does not effect the operation of the plant that is being protected.