This document defines the main types of rigid plastic distribution boxes, dimensions, safety, designation, marking and labeling. ISO 18616-1:2016 is designed for general purpose applications in a returnable transport system. Site selection requirements: The distribution box should be installed in an area close to the power supply to reduce. Choose the right box based on environment (indoor/outdoor), load capacity, and durability. Check for proper IP/NEMA ratings and material quality. Practice good wiring: secure. Distribution box certification requires standardized testing processes and comprehensive documentation to verify safety and performance. A unit that lacks corrosion protection fails within months in humid or chemically aggressive.