A surge absorber is used to protect equipment such a communication line, e.g. a telephone line connected to a telephone and telecopier, and a line for a cable television and a cable radio and the like, as well as a device, e.g. semiconductor device, from a lightning surge.
A protection function of the surge absorber is to protect a communication device connecting communication lines when the communication line interconnects the source line to load overcurrent or overvoltage on the line, which will heat the breaker fuse wire so as to melt the wire, thereby opening the circuit to protect the equipment from the overcurrent and overvoltage. A conventional surge absorber is disclosed in Japanese Patent Publication No. 63-11022. Further, the inventors disclose in Japanese Patent Publication No. 63-205026/1988 that a low melting point metal wire is provided in contact with the surface of a microgap surge absorbing element so that the heat generated by overvoltage or overcurrent charged in the surge absorbing element will easily and rapidly melt the low melting point wire, thereby, opening the circuit. The structure of mounting the low melting point metal wire on the surface of the surge absorbing element is housed within a case of inorganic material.
Heretofore, such a surge absorbing element exhibiting a protection function has been individually used in a communication line, or a line to earth. As shown in FIG. 3, communication equipment is individually connected to a surge absorbing device. For example, when an overvoltage or overcurrent is charged through T, R and then G in FIG. 3, the surge absorbing component B initially discharges, so as to melt the lower melting point metal wire in the component B, and subsequently both of the surge absorbing components discharge, melting the lower melting point metal wire in the component A. Therefore, it will take about twice as much time for one surge absorbing component to melt down and to produce an open circuit.