Low-voltage distribution box should meet the national production standards. Design requirements help you follow important standards like. Solar system installers and manufacturers face a maze of conflicting standards and certification processes when designing distribution boxes for international markets. All components and technical parameters need to comply with the national standard GB7251 design. Think of your home's distribution box as the Grand Central Station of your electrical system. It is used to distribute the electricity supplied by the energy supplier to the various circuits within a building.