The main distribution box shall be set in the area close to the power supply; the distribution box shall be set in the area where the electrical equipment or loads are relatively concentrated; the interval between the distribution box and the switch box shall not exceed. The main distribution box shall be set in the area close to the power supply; the distribution box shall be set in the area where the electrical equipment or loads are relatively concentrated; the interval between the distribution box and the switch box shall not exceed. ICLG - Construction & Engineering Laws and Regulations - Taiwan Chapter covers common issues in construction & engineering laws and regulations – including making construction projects, supervising construction contracts, and dispute resolution. Making Construction Projects 2. Supervising. In this guide, we'll break down everything you need to know to install a distribution box correctly and confidently. Choose the right box based on environment (indoor/outdoor), load capacity, and durability. Check for proper IP/NEMA ratings and material quality. Ensure safe placement: install in. The dimensioning of an electrical plant requires knowledge of different factors relating to, for example, installation utilities, the electrical conductors and other components; this knowledge leads the design engineer to consult numerous documents and technical catalogues. : Conductors cross section is calculated according to various parameters for each circuit. See regulations for details of alternative options using combinations of RCD and MCB.