The terminal box is an intermediate connection link between primary equipment and secondary equipment such as control protection, metering, communication, etc. It plays a crucial role in ensuring the safe and stable operation of primary and secondary systems. The terminal box body is often made of metal material. When the outdoor temperature difference is large or the air humidity is high (especially in the rainy season), condensation and water accumulation can easily form inside the outdoor terminal box, causing equipment damage and seriously threatening the safe operation of the power grid. Taking targeted moisture-proof measures is crucial for the safe operation of the power grid.