Boxes that enclose devices or equipment supplied by 12 or 10 AWG conductors must have an internal depth at least 1-3⁄16 inch. The working space depth for panelboards up to 600V are mentioned in NEC 110. 5 feet (≈ 2 meter) high in front of the. Choose the right box based on environment (indoor/outdoor), load capacity, and durability. Ensure safe placement: install in dry, accessible areas with good ventilation and at appropriate height (typically ~1. This height also safeguards the box from potential. For outdoor distribution boxes with significant wire bending: 1. It is recommended to use a. For distribution boxes that handle only lighting circuits or small power loads, if the incoming wire size is less than 10 square millimeters and the number of circuit switches is fewer than 20, the width of the box should be calculated by summing the width of the switches and adding an additional.