Abstract: This study presents the investigation’s characteristic’ physical flashing of Long Flashover Arrester (LFA) by varying the breadth of ring components under the 1.2/50 micro sec positive impulse voltage. The breadth of the ring was various sizes at 0.25, 0.5, 0.75, 1.0, 1.25 and 1.5 cm. The gap space for specimen was determined 0.5 cm with a diameter of 2.2 cm. When applied the 1.2/50 micro sec positive impulse voltages to 9-150 kV. The results showed that at the level of 0-60 kV the LFA with different ring’s breadth have the same flashover length. The flashover length of LFA under 1.2/50 micro positive impulse voltage was longer than negative impulse voltage when adjusted the applied voltage level >81 kV and the explicit difference of flashover lengths increased when increased the positive and negative impulse voltage to 130 kV.