A special device for the sheath protector to prevent lightning strikes and induced overvoltages from damaging the cable sheath. The sheath protector is connected between the high voltage cable sheath and the ground, and is connected by bolts and cable sheaths. Put into use. When installing, the tension of the end of the high-voltage outlet end should not exceed 145N. The insulation level of the connecting wire should not be lower than the insulation level of the outer sheath of the cable to be protected, and the connection circuit should be as short as possible. The device must be reliably grounded. The layer protector adopts ZnO varistor as the protection component, has no series gap, has good protection characteristics, and has excellent nonlinear volt-ampere characteristic curve. It not only has the advantages of porcelain sleeve metal oxide arrester, but also has good electrical insulation performance. High electrical strength, anti-leakage, anti-corrosion, heat resistance, cold resistance, aging resistance, explosion-proof and other advantages and good chemical stability, water repellency, sealing. We can produce a wide range of single-core power cable lines. The metal sheath used to protect the cable is protected from various overvoltages. In order to better meet the needs of the market and facilitate the user to install and use it on site, our company has further developed the direct grounding box and sheath of the cable sheath. Several forms of protection and cross protection, and other Internet sheath sheath grounding. Various cable sheath grounding device produced by our company have been widely used in the various electrified railway system, and achieved good operating experience.