Requirements for grounding length of temporary distribution boxes

Temporary distribution boxes must remain continuously grounded for the entire duration they are in use, from installation until removal, to ensure safety and compliance.

Continuous Grounding Requirement

Temporary distribution boxes, often called spider boxes, must provide a continuous path to ground for fault current throughout their use on a construction site or temporary setup. This grounding is not limited to a specific time frame; it must remain active for the full duration the box is energized. Once the temporary installation is no longer needed, the box and associated wiring must be removed immediately or upgraded to meet permanent wiring standards.

Grounding Conductor Specifications

Earth leads should be colored yellow and green, made of stranded copper or copper alloy, with a cross-section of at least 6 sq.mm. All connections and joints must be secure using efficient clamps or couplings, and non-ferrous materials are recommended. The grounding conductor should run within the same cable, cord, or raceway as the circuit conductors to maintain a low-impedance path for fault current.

Additional Safety MeasuresGFCI protection is required for all 120V single-phase receptacles not part of permanent wiring. Temporary boxes should be externally grounded even if internally grounded. Cables carrying voltages above 65V should have continuous metal armor or sheath effectively earthed.

Buried cables should be set at least 0. 2 meters below ground for temporary installations and protected with tiles or conduit.

Summary

In practice, a temporary distribution box remains grounded for as long as it is in service, ensuring a continuous, low-impedance path to ground. Grounding should be properly installed, maintained, and tested before use, and the system must be disconnected and removed immediately once the temporary work is complete. This approach minimizes the risk of shock, electrocution, and fire hazards on the site.