Dual power supply specifications require you to understand

Usually, we think of dual power supply as coming from two power supplies (different properties), and of course there are two feed lines; one for use and one for backup. If it refers to the power supply, then it is dual power supply. If one-use-one-standby refers to the feeder line, it cannot be called dual power supply. Dual power supply is more reliable than dual circuit, but for a single building, there seems to be no difference between the two. In many cases, there are two incoming lines. One situation of dual power supply is like this: the two incoming lines are connected from different regional substations; and correspondingly, there is a situation of dual circuit like this: the two incoming lines are connected from different busbars of the same regional substation. Therefore, the circuit in "double circuit" refers to the circuit coming out of the regional substation. Dual power supplies have different power sources and are independent of each other. When one power supply is powered off, the second power supply will not be powered off at the same time and can meet the power supply of primary and secondary loads. The double loop generally refers to the end. After one line fails, the other backup loop is put into operation to supply power to the equipment. The two circuits may be from the same power source or from different power sources.

According to my country's relevant design regulations, Class I and Class II loads should be powered by dual power supplies. When the I load loses power, it may cause equipment and personal accidents, and when the II load loses power, it may cause equipment accidents.

Dual power supplies for Class I loads should be set up with automatic mutual switching. When one side of the power supply disappears, the backup power supply will be immediately switched on and the working power supply will be tripped;

The dual power supply of Class II load can be turned on manually or manually by remote control.