Direct current system expansion device

A direct current system expansion device disclosed by the present invention comprises a box body, air switch groups, indication lamp groups and an input power supply, the box body is provided with a wire inlet hole, the box body is provided with a plurality of rows of air switch groups at intervals, each row of air switch groups comprises a plurality of air switches, the box body is provided with a plurality of rows of indication lamp groups at intervals, and each row of indication lamp groups comprises a plurality of indication lamps. Indicator lamps of each row of indicator lamp groups are connected with the air switches of each row of air switch groups in a one-to-one correspondence mode, the input power supply is a direct-current power supply provided by standby air switches in a direct-current system, each row of air switch groups is connected with one standby air switch through a power line, and the power line penetrates through the wire inlet hole. The direct current system expansion device can solve t