Surge, also known as surge, as the name suggests, is an instantaneous overvoltage that exceeds the normal operating voltage. Essentially, a surge is a strong pulse that occurs only in a few millionths of a second. Possible reasons for surge generation include bulky equipment, short circuits, power switching, or large engines. Products with surge blocking devices can effectively absorb sudden and huge energy, protecting connected equipment from damage. Surge protector, also known as lightning arrester, is an electronic device that provides safety protection for various electronic equipment, instruments and communication lines. When a sudden peak current or voltage occurs in the circuit or communication line due to external interference, the Surge protector can shunt in a very short time, so as to avoid the damage of surge to other DC Surge protector devices in the circuit. The graded protection of Surge protector (also called surge arrester) needs to release the lightning energy to the ground gradually through graded discharge because of the huge lightning energy. The first level lightning arrester can release direct lightning current or the enormous energy transmitted by transmission lines when subjected to direct lightning strikes. For places that may be directly struck by lightning, primary lightning protection must be implemented. The second lightning arrester is a protective device for the residual voltage of the previous lightning arrester and induced lightning strikes in the area. After the energy of the previous lightning stroke is absorbed, there is still a large part of energy for the device or the third arrester. The DC Surge protector needs to be further absorbed by the second arrester. At the same time, the transmission line through a lightning protection device will also induce lightning Electromagnetic pulse radiation LEMP. When the line is long enough, the induced lightning energy will become large enough, so the second lightning protection device needs to further release the lightning energy. The third lightning protection device protects LEMP and the remaining lightning energy passing through the second lightning protection device. The length of the connection should be as short as possible. One of the essence of device protection is to ensure that the high voltage of the circuit is less than the high withstand voltage of the device. The protection level of surge protectors needs to be selected according to the specific protected equipment. One rule to observe is that the wiring length from the grounding terminal of the surge protector to its protective circuit breaker (fuse) shall not exceed 50 cm, and the feeder of the DC Surge protector standby equipment to be protected must be correctly connected with the surge protector terminal and the protective circuit breaker terminal. The phase line, zero line and ground wire must be closely connected to reduce the surface area of the circuit. The wiring of the incoming and outgoing lines of the Surge protector must be independent of each other to reduce the interference to the protected line. The cables must be laid flat on the metal frame of the distribution cabinet to reduce the circulation of the frame and enhance the effectiveness of shielding interference. If the protected load is particularly sensitive to overvoltage, but the distribution box is made of plastic, the plastic distribution box must be replaced with a metal distribution box. In any case, it is necessary to check whether the metal frame of the distribution cabinet is grounded through a short circuit. Finally, if shielded cables are used, invalid additional cable lengths must be removed, otherwise the shielding effect will be reduced.