Serves as the primary distribution point for the entire project, directly connected to the transformer providing 0. Does not supply power directly to end-use equipment but acts as a centralized power distribution hub. 4kV), power distribution is achieved through three levels of distribution boxes: the main distribution board, secondary distribution boards, and tertiary distribution boards. Equipment inside usually includes isolating switches, circuit breakers, and residual current devices (RCDs). Supplies power to specific buildings or floors. Note: The three-level power distribution is mainly to ensure that each power-consuming device has electricity available; each power-consuming device can be used.