As for the equipment inside, there are certain differences: the first level distribution cabinet generally has isolation switches, circuit breakers, leakage protectors, etc. 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. Supplies power to specific buildings or floors. A feeder usually begins with a feeder breaker at the distribution substation. Panelboards shows typical examples of panelboards.