Is the lightning rod the lightning needle?
The grounding resistance is only measured, and it is impossible to measure it. It requires professional staff. Of course, the smaller the grounding resistance, the better, but the smaller the cost of materials.
The 2 inch steel tube is used as the grounding electrode, and the upper part is connected by flat steel, and the grounding resistance is less than or equal to 10 ohms. Copper material is not necessary unless it is strongly corrosive to geological conditions, because copper is not more effective in reducing ground resistance. The grounding resistance mainly depends on the equivalent diameter of the grounding electrode.
So the lightning rod should have good grounding and meet the requirements of the grounding resistance to the lightning current into the earth, no two counter attack caused by electrical equipment fault in the room and other accidents, not because of the earth potential gradient caused by lightning when the inflow have different step voltage, resulting in personal safety issues.
The lightning is commonly used lightning rod. When a large number of charge clouds drifting over the lightning rod, rod tip can charge automatically saved and clouds on the contrary, the electric field intensity distribution of lightning rod tip very close, so it is easy to charge in the conduction and cloud tip generation arc, which will charge the rod into the underground.
