Grounding Requirements for Machine Tools: Ensuring Safety with Ground Resistance and Multiple Grounding

Earth resistance ≤4Ω; If the earth resistance requirement cannot be guaranteed, it must be grounded again. The method is to purchase 3 standard copper rods with a diameter of 30mm (3m each), arrange them near the machine tool distribution box, without obstructing the passage of personnel and normal work areas, such as wall corners or column corners, with a spacing of not less than 6m, vertically inserted into the ground, with the top exposed to the ground about 0.2m. Use copper wires with a cross-sectional area of not less than 16mm² to weld or hinge together, and then use wires of the same material and model as the power supply phase to connect to the protection line (PE) connection board of the machine tool power distribution box.