In the cathodic protection system is only an indispensable part of the spark gap, it is mainly installed in the insulation joint, storage tank lightning protection grounding network and other places, to prevent the over-voltage due to lightning or misoperation caused by the breakdown of the insulation flange or insulation joint. The principle of use of spark gap is as follows: it is open in normal state. Only when it is struck by lightning or encounters fault voltage, the spark gap automatically short-circuits, and a large amount of current is discharged into the ground grid.

The primary purpose of the use of spark gap is to avoid damage caused by sudden overvoltage to persons and equipment in contact with the protected pipe. Explosion-proof spark gap installation: the maximum discharge current of the explosion-proof spark gap is 50KA, the nominal discharge current is 100KA, the impact breakdown voltage is less than 2.5kV, ac breakdown voltage is less than 1.2kV, the spark gap length is 75mm, the spark gap diameter is 50mm, connecting cable is 25mm2 cable, using M10 bolt nut, The total length of the cable can be adjusted as needed.