Location of secondary power distribution boxes on construction site

Secondary power distribution boxes should be installed below the main distribution box, near concentrated electrical loads, in ventilated, dry, and accessible locations, with proper spacing and height for safety and maintenance.Placement and HierarchyOn a construction site, the power distribution system is organized in levels. The main distribution box is installed closest to the power supply, while secondary distribution boxes are positioned below it, and switch boxes are installed below the secondary boxes . This hierarchical setup ensures efficient power flow and easy maintenance.Proximity to LoadsSecondary distribution boxes should be located near areas with concentrated electrical equipment or loads. The distance between the distribution box and its associated switch box should not exceed 30 meters, and the horizontal distance between a switch box and the fixed electrical equipment it controls should not exceed 3 meters . This minimizes voltage drop and ensures reliable power delivery.Environmental and Safety ConsiderationsInstall boxes in ventilated, dry, and normal temperature areas. Avoid locations exposed to gas, steam, liquids, vibration, impact, or heat sources .Ensure enough space for two people to work simultaneously around the boxes, and keep the area free of obstacles, weeds, or shrubs .Boxes should be rainproof and dustproof, and made of iron plate or high-quality insulating material with a minimum thickness of 1.5 mm .Height and AccessibilityFixed distribution boxes and switch boxes should have their bottom surface 1.3–1.5 meters above the ground.Mobile boxes should be 0.6–1.5 meters above the ground .Wire inlets and outlets should be at the bottom of the box, bundled with waterproof bends, and never at the top, side, back, or door .Separation of CircuitsPower and lighting circuits should be installed in separate boxes or clearly separated within the same box .All connections should use insulated wires, with no exposed live parts, and protective neutral connections should be properly terminated .SummarySecondary distribution boxes on construction sites are strategically placed below the main distribution box, close to concentrated loads, and installed at safe heights in dry, ventilated, and accessible locations. Proper spacing, separation of circuits, and adherence to safety standards ensure reliable power distribution and facilitate maintenance .