The transformer terminal box is a wiring and protection unit mounted on the transformer body; it primarily serves to connect the transformer to external secondary cables and centrally manage the output of non-electrical signals, such as temperature and oil level readings. It functions as the transformer's "external interface box," facilitating maintenance and ensuring the safety of internal circuitry.
They are primarily used for terminal connections in secondary circuits-such as those for circuit breakers, voltage transformers, power transformers, and metering equipment-at power plants and substations. They also serve as maintenance power sources for substations and are used in industrial facilities for power distribution boxes, power control boxes, lighting distribution boxes, and terminal boxes. Constructed from materials such as steel plate or stainless steel, they feature an IP54 protection rating.