Door designed for Acti 9 Isobar B-type distribution boards, specifically those with 24 triple-pole (TP) ways. It serves as a protective and aesthetic front cover, ensuring safety by shielding internal components and providing a clean, professional finish to the distribution board. Standard Equipment Shielded doors from 0. 9 m wide personnel doors to 5 m wide (or more) equipment doors. These doors are not just simple mechanical. The WPN Waterproof Distribution Box is a surface-mount enclosure using a rigid ABS body with a smoked PC transparent door. Our engineers will be. Below, we break down the exact shielding specs, material choices, assembly methods, and international standards you need to know.