A terminal box is an electrical enclosure equipped with organized terminal blocks designed for frequent access, testing, and modification of connections. It serves as a control interface or distribution point in industrial systems. Function: Junction box = wire splicing; Terminal box = wire-to-terminal interface. Often a subtle, yet crucial, endpoint device within a building's advanced HVAC system, the Terminal Box serves as the definitive control point, meticulously regulating the conditioned air before it is delivered into a specific space via diffusers. This comprehensive guide is engineered to demystify. The answer is simple, but profound: An electrical box is defined by its mission, not its material.