When the wall is built, the reserved hole shall be about 20 mm larger than the length and width of the distribution box. How to choose a distribution box of the right size for a project based on load current? Get it right the first time with this comprehensive guide If you're like most electrical professionals, picking the right distribution box for your project can feel like navigating a maze. This process also involves selecting appropriately sized wires and cables, choosing the correct size of MCBs (Miniature Circuit Breakers), and calculating the ratings for plugs and. How to design distribution box or DB size ? - YouTube How to design distribution box or DB size ?When the electric box is only a lighting electric box or a small power, and the incoming line is less than 10 square, if the number of switch digits is less than 20, the width of the switch is added and 20mm on each side is the width of the electric box, and the height is the switch height Add. This section explains the measurement points of the enclosures of distribution boards, switchboards, control panels, and cubicles (which require short delivery times and improved quality) as well as the problems related to these measurements. It also introduces example solutions to measurement. Design Distribution Box of one House and Calculation of Size of Main ELCB and branch Circuit MCB as following Load Detail. Power Supply is 430V (P-P), 230 (P-N), 50Hz. 6 for Non Continuous Load & 1 for Continuous Load for Each Equipment. Branch Circuit-1: 4 No of 1Phase.