The lightning arrester shall not be connected to the grounding grid by two grounding connections. This is because: lightning when the lightning current into the earth, because of the high frequency characteristics of lightning current, transient high potential will result in higher lead in, so by the lightning rod to fuse grounding net should be as short as possible, otherwise it will lead to a high potential for other objects around two times counter. At the same time, because the two ground connection to the main grounding grid that trigger lightning current good shunt, resulting in high voltage wire near. Therefore, the lightning rod should be directly connected with the grounding grid, if not connected arresters should be near the grounding resistance of grounding grid is an independent 10 ohm set in the lightning around the grounding grid should be made of pressure ring, as far as possible to reduce the step voltage.