Requirements for the installation distance of distribution boxes

Distribution boxes should generally be installed 1.3–1.5 meters above the ground for fixed boxes, with horizontal spacing not exceeding 30 meters to switch boxes and 3 meters to controlled equipment.

Vertical Installation Height

• Fixed distribution boxes: The bottom of the box should be 1.3 to 1.5 meters above the ground, ensuring ergonomic access for routine maintenance, switch operation, and inspection .
• Mobile distribution boxes: The bottom should be 0.6 to 1.5 meters above the ground, allowing flexibility while maintaining accessibility .
• Wall-mounted boxes: Typically installed 1.2 to 1.5 meters from the floor, with uniformity across similar boxes within the same building, allowing a deviation of no more than 10 millimeters .
• Some sources suggest 1.5 to 1.8 meters for general operation and inspection convenience, especially in residential or commercial settings .

Horizontal Spacing and Proximity

• The distance between a distribution box and its associated switch box should not exceed 30 meters .
• The horizontal distance between a switch box and the fixed electrical equipment it controls should not exceed 3 meters .
• Each piece of electrical equipment should have a dedicated switch box with its own residual current device (RCD) to ensure safety .

Environmental and Safety Considerations

• Install boxes in dry, well-ventilated, and easily accessible locations, avoiding areas with moisture, corrosive gases, or extreme heat .
• Maintain sufficient operating space around the box, typically enough for two people to work simultaneously, to facilitate maintenance and emergency handling .
• Ensure proper grounding of the metal box, electrical installation board, and all metal components inside the box .
• Use locks on all distribution box doors to prevent unauthorized access .
• Avoid placing temporary equipment or sundries inside the boxes to maintain safety and operational integrity .

Summary

For safe and efficient installation:

• Vertical height: 1.3–1.5 m (fixed), 0.6–1.5 m (mobile)
• Horizontal spacing: ≤30 m to switch box, ≤3 m to controlled equipment
• Environment: Dry, ventilated, accessible, and free from corrosive or hazardous conditions
• Safety: Grounding, locks, dedicated RCDs, and clear working space Following these standards ensures ergonomic access, operational efficiency, and compliance with electrical safety regulations.