A gas tube fail safe device for elongated three element gas tubes having a centrally disposed electrode and a pair of end electrodes. The device includes an elongated planar body (21) having bent up end edges (26-27) forming end electrical contact terminal insulation sleeves (30-31) forming fusible elements. Centrally disposed tabs (33-34) resiliently engage a pin carried by the center electrode of the gas tube. In a second embodiment, a pair of shorting plates (50-51) overlie an air gap insulative member (60) having lines of small orifices (66) which provide air gaps through which excess voltage surges may arc to provide a backup function equivalent to that of the gas tube.