Abstract: An arrester having at least two stacks of non-linear resistors connected in series, an arcing gap device connected to shunt one stack of resistors when the gap means sparks over, and a hermetically sealed housing enclosing the resistor stacks and arcing gap device and filled with sulfur hexafluoride gas having a gauge pressure not less than 2 kg/cm.sup.2. The impedance of the one resistor stack is from about 15% to about 35% of the total impedance of the two resistor stacks when the arcing gap means sparks over, and the rated voltage of the arrester is not less than about 50 KV.

Abstract: In an arrester comprising a characteristic element made up of a stack of a plurality of metal oxide resistors, parallelly connected capacitor and a linear resistor are connected between the characteristic element and ground, and voltage drop across the linear resistor is used to light a neon lamp or to operate an alarm device for detecting deterioration of the characteristic element. To protect the capacitor and the linear resistor at the time when the arrester operates, a nonlinear resistor may be connected in parallel with the capacitor and the linear resistor.