Key requirements include temperature rise tests 2, IP rating verification 3, short-circuit withstand testing 4, detailed technical files, and compliance with regional standards like IEC 61439 5. This ultimate guide explains what a distribution box does, its internal. Indication Lights: These provide visual availability and status of mains power supply. Each component plays a specific role. Smart DB boxes have extra parts like energy monitoring units and communication modules. They control how much power is enough for a perfect working experience.