There should be a distance of m between the main distribution box and the sub-distribution boxes

There is no fixed distance required between a main distribution box and sub-distribution boxes; placement is guided by accessibility, safety, and practical wiring considerations.Code and Safety ConsiderationsThe National Electrical Code (NEC) does not specify a maximum distance for subpanels from the main panel, but it emphasizes safe working clearances. A minimum clear space of 3 feet in front of the panel, at least 30 inches wide, and a vertical clearance of 6 feet 7 inches is required to allow safe access for maintenance and emergency operations . Subpanels should not be installed in bathrooms, closets, or above stairways due to safety hazards . IEC and BS 7671 standards also focus on safe access and environmental conditions rather than a fixed distance. Panels should be installed in dry, ventilated areas with adequate space for maintenance and inspection .Practical Installation GuidelinesVoltage Drop and Feeder Length: While there is no strict distance limit, longer feeder runs from the main to sub-distribution boards can cause voltage drop. Designers often place subpanels closer to the load centers to minimize this effect .Conduit and Cable Management: For conductors #4 AWG and larger, minimum spacing between conduits is recommended to preserve bend radius, typically 6 to 8 times the conduit diameter .Accessibility: Subpanels should be easily reachable for maintenance, with doors opening at least 90 degrees and sufficient headroom .Height Recommendations: Residential distribution boards are typically installed around 1.5 meters from the floor, while industrial setups may vary depending on equipment and space .Best PracticesLabel all circuits and maintain single-line diagrams for clarity .Ensure phase balancing and allow space for future expansion .Use modular designs and proper grounding to enhance safety and reliability .Avoid placing subpanels in areas prone to moisture or obstruction . Summary: There is no mandatory distance in meters between the main and sub-distribution boxes. The focus should be on safe access, minimizing voltage drop, proper conduit spacing, and practical layout to ensure a reliable and maintainable electrical system .