Grounding wire and grounding body of the distribution box

Proper grounding of a distribution box involves connecting a correctly sized copper wire from the box's grounding terminal to the main grounding system, ensuring low resistance and secure connections. Steps for Grounding a Distribution Box1. Identify the Grounding Point Open the distribution box and locate the grounding bar (PE bar) or terminals marked with a grounding symbol.

This is the designated point for connecting the grounding wire inside the box. 2. Connect the Power Ground Wire Use a yellow-green insulated copper wire with a cross-sectional area meeting local standards (e.g., 10 AWG in the US or 6 mm² elsewhere).

Strip the wire end, attach it to the PE bar or grounding terminal, and tighten the screw securely to ensure a firm connection. 3. Ground Internal Components If the distribution box contains electrical components that require grounding, connect them to the PE bar using copper wires.

This ensures all internal equipment is safely grounded. 4. Connect to the Main Grounding System Attach a wire from the distribution box mounting plate or grounding terminal to the central grounding point or ground rod.

For metal boxes, ensure a continuous conductive path, possibly using braided copper tape for flexible connections between the door panel and box body. 5. Ensure Low Resistance The total grounding resistance should be less than 0.

1 Ohm for industrial applications or below 25 Ohms for general installations. Use a multimeter or ground resistance tester to verify the connection. 6.

Use Anti-

Loosening Measures For metal boxes, use serrated washers or conductive grease at connection points to maintain low contact resistance and prevent corrosion over time. 7. Mark and Inspect Clearly label grounding connections for maintenance and inspection.

Regularly check for loosened screws or corrosion to maintain safety.

Additional Considerations

For long tool cables or multiple spindles, additional grounding wires may be required to maintain low resistance in parallel with the tool cable. Plastic distribution boxes require a metal grounding point or rod connection to ensure proper dissipation of fault currents. Always follow local electrical codes and standards, and have grounding work performed by a qualified electrician.

By following these steps, the distribution box and all connected components will be safely grounded, reducing the risk of electrical faults, surges, and equipment damage.