HVI cable (high-voltage-resistant insulated conductor) in a support tube, to maintain the separation distance from electrically conductive parts in accordance with DIN EN 62305-3 (VDE 0185-305-3), in order to prevent dangerous flashovers between parts of the external lightning protection and internal, conductive parts (electrical system, pipes, etc.). To prevent creeping discharges, the HVI cable is equipped with a special external sheath that enables high lightning impulse voltages to be diverted to a reference potential. HVI cable design (gray), with internal end closure and PA spring element in the support tube (length 3200 mm) with air-termination tip (D10 mm length 1000 mm) and an earth connection element. Equivalent separation distance s = 75 cm (in air), s = 150 cm (solid building material).