These unbalanced circumstances in the system result in single-phasing, overloading, and overheating situations, and the return of current to neutral, as well as increased power system investment and operational expenses. As for the equipment inside, there are certain. After stepping down the voltage through the transformer's low-voltage side (0. 4kV), power distribution is achieved through three levels of distribution boxes: the main distribution board, secondary distribution boards, and tertiary distribution boards. This device makes sure power goes to big machines safely and quickly. Primary distribution board: In fact, this kind of.