NEC Requirements for Outdoor Distribution Boxes: Complete specification guide for outdoor electrical distribution boxes covering NEC Article 312 requirements, NEMA ratings, sizing calculations, and selection criteria for commercial and residential applications. It takes the incoming power and safely distributes it to different circuits throughout your building. However, the key to. These weatherproof enclosures are critical safety components in any exterior electrical system, from landscape lighting to pool equipment. Site selection requirements: The distribution box should be installed in an area close to the power supply to reduce. A distribution box is a low-voltage electrical enclosure that receives incoming power and distributes it safely to multiple outgoing circuits through protective and switching devices such as MCBs, RCDs, RCBOs, fuses, isolators, busbars, neutral bars, earth bars, and surge protective devices.