SURGE PROTECTION DEVICE

To provide a surge protection device that can be applied to a communication circuit without the need of a power supply, prevents an increase in discharge voltage of an SPD, and allows output of an alarm when carrying a lightning surge current, operation display of the SPD, and inspection of functions.SOLUTION: A surge protection device comprises: a conductive member 40 that is connected in series with an SPD through which a lightning surge current exceeding a predetermined threshold flows and discharges the lightning surge current toward the ground; a driving member 50 in which, during overheating of the conductive member 40 through which the lightning surge current flows, a hot-melt member 41 interposed between the conductive member 40 and the driving member melts and is released from fastening to the conductive member 40, and that is movable by a predetermined force F1; a switch operation member 20 that is driven by the moved driving member 50 and turns on an alarm switch 30; and a display 21a that is formed on the switch operation member 20 and displays the on/off state of the alarm switch 30. The predetermined threshold is set to be a value equal to or less than a rating lightning surge current of the SPD.SELECTED DRAWING: Figure 1 【課題】電源を不要にして通信回路への適用を可能にし、ＳＰＤの制限電圧の上昇を防ぐと共に、雷サージ電流通電時の警報出力やＳＰＤの動作表示及び各機能の点検を可能にしたサージ防護装置を提供する。【解決手段】所定の閾値を超える雷サージ電流が流れたＳＰＤに直列に接続されて雷サージ電流を接地側に放流させる導電部材４０と、雷サージ電流が流れた導電部材４０の過熱時に、導電部材４０との間に介在する熱溶融材料４１が溶融して導電部材４０との固着が解放され、かつ所定の力Ｆ１によって移動可能な駆動部材５０と、移動した駆動部材５０により駆動されて警報スイッチ３０をオンさせるスイッチ操作部材２０と、スイッチ操作部材２０に形成されて警報スイッチ３０のオン・オフ状態を表示する表示部２１ａと、を備え、前記所定の閾値をＳＰＤの定格雷サージ電流以下の値に設定する。【選択図】図１