Ground wire of small outdoor distribution box

Use a properly sized copper grounding wire connected from the distribution box to a certified grounding system, ensuring low resistance and secure connections.

Wire Type and Size

For outdoor distribution boxes, copper conductors are recommended for all buried or exposed grounding runs, as aluminum corrodes over time and can compromise safety.

In the U

S, a 10 AWG (5. 26 mm²) wire is typically used for small distribution boxes, while in other markets, a 6 mm² wire is standard. For connections between mounting plates and internal components, larger wires such as 6 AWG (13.

29 mm²) may be used to maintain low resistance in longer cable runs.

Connection Points

Grounding Bus (PE Bus): Connect all internal components that require grounding to the PE bus inside the box using copper core or braided wires. Box Body: The metal enclosure should be connected to the PE bus via a dedicated grounding bolt or terminal marked with a grounding symbol. Door Panels: For stainless steel or IP65 enclosures, use braided copper tape between the door and box body to maintain continuity and prevent corrosion.

External Grounding: Connect the box's mounting plate to the main grounding electrode or factory central grounding point to ensure the system is properly earthed.

Grounding Resistance

The total resistance between the distribution box and the grounding system should be less than 0. 1 ohm to ensure effective fault protection. For longer cable runs, calculate parallel resistances to confirm the total resistance remains below the recommended threshold.

Installation Tips

Avoid aluminum conductors for buried or outdoor runs; use only copper. Clean contact surfaces and use anti-loosening washers to maintain low resistance and prevent oxide layers from forming. Separate neutral and ground terminals inside the box to prevent ground loops and ensure fault currents are safely diverted.

Test resistance after installation using a multimeter to verify proper grounding. Use certified materials from reputable suppliers to avoid corrosion and ensure long-term reliability. By following these guidelines, your outdoor small distribution box will have a safe, low-resistance grounding system that protects both equipment and personnel from electrical faults.