Distance between the third-level box and the distribution box

The distance from a tertiary (third-level) distribution box to its secondary distribution box should not exceed 30 meters. In a three-level electrical distribution system, power flows from the primary distribution board to secondary distribution boxes, and finally to tertiary switch boxes that control individual electrical equipment. To ensure safety, efficiency, and compliance with hierarchical distribution principles, the distance between a secondary distribution box and a tertiary switch box should be kept as short as possible, with a maximum of 30 meters.

Additional Guidelines

Horizontal distance to equipment: The horizontal distance between a tertiary switch box and the fixed electrical equipment it controls should preferably not exceed 3 meters. One machine, one switch principle: Each tertiary box should control only one piece of equipment, ensuring proper protection and avoiding bypassing the hierarchical structure. Leakage protection: Both secondary and tertiary boxes should include appropriate leakage protection devices to enhance safety.

Placement considerations: Distribution boxes should be located near areas with concentrated electrical loads, and tertiary boxes should be installed close to the equipment they serve to minimize cable length and voltage drop. Following these distance guidelines ensures efficient power distribution, reduces energy loss, and maintains safety standards in construction and building electrical systems.