Construction site electrical distribution boxes typically use either single-phase (230V) or three-phase (400V) power, depending on the load requirements of the site.

Single-Phase vs. Three-Phase Site Boxes

Single-phase site boxes are generally used for standard tools, lighting, and low-power equipment. They operate at 230V and are sufficient for small-scale construction tasks where heavy machinery is not involved . Three-phase site boxes are required when the site has high-power machines such as compressors, large motors, or other industrial equipment. These boxes operate at 400V and provide a more stable and efficient power supply for heavy loads . Three-phase systems distribute power across three conductors, each 120 degrees out of phase, which ensures a constant flow of electricity and reduces the risk of overloads .

Advantages of Three-Phase Distribution Boxes

• Higher power capacity: Can handle larger loads without overloading circuits .
• Stable power delivery: Reduces voltage fluctuations and ensures smooth operation of motors and heavy equipment .
• Flexibility: Can supply both three-phase and single-phase circuits from the same box, allowing simultaneous use of high- and low-power devices .
• Safety: Equipped with breakers and fuses to prevent short circuits, overloads, and electrical hazards .

Selection Considerations

When choosing a site box, consider:

• Total load: Sum of all equipment that will run simultaneously.
• Voltage requirements: 230V for standard tools, 400V for high-power machinery.
• Compliance: Must meet local standards (e.g., NF C 15-100 in France) and have appropriate IP and IK ratings for outdoor use .
• Professional installation: A licensed electrician should connect the box to ensure safety and proper operation . In summary, construction sites commonly use three-phase distribution boxes for heavy machinery and single-phase boxes for standard tools and lighting, with the choice determined by the total power demand and type of equipment on site .