Choose the right box based on environment (indoor/outdoor), load capacity, and durability. Check for proper IP/NEMA ratings and material quality. In this guide, we'll break down everything you need to know to install a distribution box correctly and confidently. Site selection requirements: The distribution box should be installed in an area close to the power supply to reduce. The National Electrical Code (NEC) requirements might seem like bureaucratic red tape, but they're more like the safety rails that keep everything running smoothly and prevent dangerous surprises. At the same. The IEC (International Electrotechnical Commission) and BS 7671 (British Standard for Electrical Installations) both provide essential requirements for electrical installations, including those for fuse boards like garage unit, consumer unit and distribution board.