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. Design requirements help you follow important standards like. Many customers advise us the need to have a dimensional criteria for enclosures used as distribution panels, motor starters, control, signaling and marshalling boxes. The supplier shall submit Type Test Repor of the Isolator for approval of Employer before commencement of supply.