Combination transformers, commonly known as American box transformers, have excellent performance such as reliable power supply, reasonable structure, fast installation, flexibility, easy operation, and small size. They are widely used in various places such as industrial parks, residential areas, commercial centers, urban roads, and high-rise buildings. This type of product is different from the European box transformers currently produced in China in that: American box transformers are integrated with transformer cores, high-voltage load switches, and protection fuses and other equipment designed and placed in the same fuel tank, so they are smaller in size.