Portable distribution boxes are equipped with circuit breakers, fuses, and surge protection to prevent overloads and electrical hazards on-site. In this guide, we cover everything you need to know, from what they are, to what they're used for and why they're a smart investment for any temporary setup. As a protective "armor", the shell is mostly made of high-strength engineering plastics or aluminum alloys. It has the characteristics of light. Distribution boxes, or electrical junction boxes as they are sometimes called, play a vital role in electrical systems. They provide flexible, reliable electrical power in locations where permanent wiring isn't feasible or necessary.