The concept in use when dual power supplies are connected to different power sources is fault tolerance. Fault tolerance is the ability of a system to continue operating without interruption or loss of data in the event of a failure of one or more components. By connecting dual power supplies to different power sources, the system can switch to the alternative power supply or source if one fails, ensuring continuous availability and reliability.
References: CompTIA Server+ SK0-005 Certification Study Guide, Chapter 1, Lesson 1.3, Objective 1.3