Here are some factors influencing the cost of a junction box: Material: Plastic boxes are generally cheaper than metal (steel, aluminum) ones. Junction box costs range from low‑price indoor models ($10‑$60) to weatherproof units ($70‑$450), with installation averaging $100‑$300 depending on location and materials. If you're planning any electrical work, one of the small but important items on your list will be the junction box. 40 Billion by 2033, at a projected CAGR of 5. The junction box market grows with increasing investments in infrastructure development. Environmental ratings significantly impact the cost, particularly for applications exposed to the elements or specific hazards. Boxes rated for outdoor or wet locations must meet specific ingress protection (IP) or NEMA standards, which dictate their ability to repel water and dust. These. Setting up a junction box manufacturing plant requires a comprehensive market and technical assessment covering raw material procurement, utility needs, production process design, machinery specifications, infrastructure setup, and financial projections.