The box power distribution is applicable to the industrial and civil architectures as the dynamical and light distribution in 3-phase 4-wires power system, AC with the frequency of 50 Hz, voltage of 500V or lower. This power supply distribution box is used for protecting overload, short-circuit and leakage, as well as for circuit switching. It is an indoor closed device, with the protection grade of IP 30. The outdoor has a protection grade of IP65. They are complying with relevant standards of GB 7251.1 and IEC 60439-1.