When selecting the right 3 phase power distribution box for your application, prioritize models with UL/CSA certification, proper NEMA enclosure ratings (such as NEMA 3R or 4X for outdoor or harsh environments), and sufficient amperage capacity—typically ranging from 100A to 600A . When selecting the right 3 phase power distribution box for your application, prioritize models with UL/CSA certification, proper NEMA enclosure ratings (such as NEMA 3R or 4X for outdoor or harsh environments), and sufficient amperage capacity—typically ranging from 100A to 600A . When selecting the right 3 phase power distribution box for your application, prioritize models with UL/CSA certification, proper NEMA enclosure ratings (such as NEMA 3R or 4X for outdoor or harsh environments), and sufficient amperage capacity—typically ranging from 100A to 600A depending on load. From residential 100-amp panels to massive 600 amp main distribution panels in commercial facilities, this comprehensive guide will help you understand distribution board types, sizing calculations, and installation requirements to make informed decisions about your electrical infrastructure. What. That's why E-abel develops customized three-phase distribution boxes that provide safe, modular, and efficient power management — all in one compact industrial enclosure. Including compact boxes from the MERZ, ISCHL, IMST, ST ANTON, and STEYR ranges. These Distribution Cabinets are to be outdoor type nd to be fabricated out of 2 mm GI sheet steel. The body of the boxes shall have sufficient re- enforcement with suitable size of channels keeping a provision for fixin andle conforming to general. A three phase distribution box controls and guards electricity in three-phase power systems. Big buildings with many floors.