This document provides specifications for various distribution boxes including dimensions, mounting sizes, and number of ways. Done right, it ensures safety, compliance, and long-lasting performance. Check out this quick guide: Think about how many devices you need, where you will install the box, and the environment. Get this wrong and you're either wasting money on oversized equipment or risking dangerous overloads. In this guide, I'll walk you through a practical. We'll decode NEC Article 312 requirements, compare NEMA vs IP ratings, analyze busbar sizing calculations, and provide specification decision matrices for different applications. 💡 Specification Insight: NEC 312.