How thick is the cable for the mobile power distribution box

For a mobile power distribution box handling up to 63A three-phase, a mains cable of 10–16mm² is typically used, depending on insulation type and installation conditions.

Recommended Cable Sizes

Mains input cable: For mobile units with a maximum of 63A three-phase at 400V, 10mm² copper conductors with PEX, EPR, or LSZH insulation are generally sufficient if the cable is short (e.g., 2 meters) and installed "free in air" due to higher current-carrying capacity (up to 75A for 10mm² in free air at 90°C conductor temperature). For more conservative or permanent installations, 16mm² may be used to match standard 5G16mm² wiring. Internal wiring: Inside the distribution box, each phase may be split across multiple RCBOs using 2.

5mm² wires, totaling 10mm² per phase, which aligns with safe current handling for mobile applications. Flexible power cables: For temporary or mobile setups, flexible cables such as welding cable (DLO) or Type W flexible cords are preferred due to their high ampacity and ability to withstand repeated flexing.

Practical Considerations

Cable insulation: Non-PVC insulation like PEX, EPR, or LSZH allows higher current ratings and better heat resistance, which is advantageous for mobile units. Installation method: Short, free-air cables can carry more current than cables in conduits or trays, reducing the required cross-section. Connector compatibility: Ensure the cable size matches the plug and CAM switch terminals inside the box.

Using 7G10mm² LSZH cables can simplify connections compared to splitting 16mm² wires. Safety standards: Mobile distribution boxes should comply with IEC 61439 for construction and IEC 61535 for connector systems, ensuring safe operation in temporary installations.

Summary

For a mobile power distribution box with a 63A three-phase input: Mains cable: 10–16mm² copper, PEX/EPR/LSZH insulation, short length (≤2m)Internal wiring: 2. 5mm² per RCBO branch, totaling ~10mm² per phaseFlexible options: DLO or Type W cords for mobility and repeated flexing This ensures safe current handling, flexibility, and compliance with temporary installation standards.