Observations on occurrence currents by lightning surges intruding into home from various directions and an experimental study of the effect of the SPD

Lightning surges propagate into a house mainly from four directions, power distribution lines, communication lines, antenna cables and grounding lines. However lightning performance of indoor wires has not been cleared yet because of the complexity of the mechanism. Moreover, lightning protection devices such as SPDs are available, but they still are not popular because the effects of them have not been cleared. In this study, experiments were conducted with a full-scale system. In order to clarify the effects of the SPD against lightning surges from several directions, applied current for each case kept a certain level. Propagations of surge currents and over-voltages were observed in various conditions. The results confirmed effectiveness of the SPD in the switchboard against the surges from the various directions.