The recommended configuration is: 1 Main Switch: Controls the entire electrical system. X Room Socket Circuits: Each room should have its own circuit to manage regular sockets. This article guides you through selecting a distribution box that is both affordable and safe, emphasizing key features, configuration, and practical considerations. Safety is the top priority when choosing a distribution box. What Are Electrical Box Dimensions? Electrical box dimensions typically refer to: Correct dimensions ensure:. For distribution boxes that handle only lighting circuits or small power loads, if the incoming wire size is less than 10 square millimeters and the number of circuit switches is fewer than 20, the width of the box should be calculated by summing the width of the switches and adding an additional. To choose a home distribution box, you must count your circuits and add 30% spare space. Finally, choose safety devices like RCBOs and Surge Protection Devices (SPD) for the best protection against faults and lightning.