How do I choose the right distribution box? You should consider the installation environment, IP protection rating, number of circuits, electrical load, and enclosure material. Learn what a distribution box is, its types, and how to choose the right one for your project. This highly technical guide details the exact engineering criteria required for selecting, precisely sizing, and optimally configuring the correct enclosure for your specific electrical load profiles. Its arguably just as important as the components inside. This guide walks you through everything about electrical enclosure box sizes — from measurement standards and IP ratings to sizing formulas and common pitfalls.