LIGHTING ARRESTOR

PURPOSE: To prevent the side face of a varistor element from deteriorating in insulating properties so as to improve it in discharge withstand current rating by a method wherein an insulating cylinder is provided outside the varistor element. CONSTITUTION: Cylindrical varistors elements 1 and 2 are connected in series, and an umbrella-like electrode plates 13 and 14 are provided to the longitudinal ends of the connected elements 1 and 2. The electrode plates 13 and 14 are installed making their openings face outwards, and a hole whose diameter is equal to the inner diameter of the elements 1 and 2 is provided to the electrode plates 13 and 14 respectively. An insulating cylinder 8 provided outside of the elements 1 and 2 to protect them is slightly longer than the connected elements 1 and 2, and its inner diameter is set larger than the outer diameter of the elements 1 and 2 but smaller than the outer diameter of the electrode plates 13 and 14. An insulating bolt 5 is inserted into the holes provided to the elements 1 and 2 and the electrode plates 13 and 14, metal nuts 6 and 7 are fastened to the ends of the insulating bolt 5 to fix the elements 1 and 2 and the electrode plates 13 and 14.