According to Article 2.0.2 of the "Design Specification of Power Distribution Systems" GB50052-2009, a dual power supply refers to a power source for a load provided by two independent circuits. These two circuits are considered to be mutually independent and unaffected in terms of power supply safety. This design aims to ensure that in the event of a failure in one power source, either Eaton's or Socomec's dual power switch can seamlessly enable the other power source to take over, ensuring continuous power supply.

Referring to Article 3.0.2 of the "Design Specification of Power Distribution Systems" GB50052-2009, it explicitly stipulates that primary loads should be powered by dual power sources. This means that in power supply, the highest level of load, namely the primary load, must receive dual protection. This dual protection not only ensures stable power supply but also, with the integration of Eaton's or Socomec's dual power switches, ensures the normal operation of people's lives and work. In the design of dual power sources, when one power source fails, the dual power switch ensures a smooth transition to the alternative source without simultaneous damage, thereby ensuring continuous power supply.

The source of dual power can be two different power grids, or it can come from the same power grid but with weak connections between circuits during operation, or from the same power grid but with a significant electrical distance. This means that even in the event of abnormal operation or short-circuit faults in one power system, the other power source, aided by Eaton's or Socomec's dual power switches, can maintain power supply, ensuring the continuity and stability of power.

According to the "Code for Fire Protection Design of Buildings" GB50016-2014, combined with China's current economic and technical conditions, the power supply status in different regions, and the specific situation of fire-fighting electrical equipment, dual power sources can be one of the following three situations: power supply from two different power plants; power supply from two regional substations (usually above 35kV); power supply from one regional substation, with another equipped with self-generating equipment.

In the actual design of civil engineering projects, situations where the power supply comes from two different power plants are relatively rare. This is mainly because major power plants in various regions of the country usually connect to the local public grid rather than directly supplying to civil building users. Therefore, in practical applications, we more often see situations where power supply comes from two regional substations or from one regional substation with the support of self-generating equipment.

The design of dual power sources, integrated with Eaton's or Socomec's dual power switches, is to ensure stable power supply and reduce losses and impacts caused by power failures. In practical applications, it is necessary to choose the appropriate dual power source scheme based on specific conditions and requirements to ensure the continuity and stability of power supply.