The function of the grounding wire is: if there is no grounding, leakage will occur, and the leakage current will conduct electricity through the human body-earth, which will cause personal injury. So it must be grounded. The grounding wire (commonly known as grounding) is to form a loop, otherwise there is no loop, there is no current, and no current can be arc welding.The working principle of arc welding is that electric welding is a welding operation realized by using an electrode to melt a place where a metal part needs to be connected by a high temperature of an arc. Its working principle is: through the commonly used 220V or 380V voltage, reduce the voltage through the transformer in the welding machine, enhance the current, and make the electric energy generate huge arc heat to melt the electrode and steel, and the welding rod melts to make the fusion between the steel more .