Which type of automatic bus transfer switches are considered nonselective?

The correct choice indicates that Application 8S Automatic Bus Transfer Switches (ABTs) are considered nonselective. Nonselective ABTs operate by connecting a load to a backup power source (such as a generator or another power line) without determining the specific load being served or prioritizing which circuits should be powered. Instead, these switches provide a straightforward approach to transferring power, essentially supplying power to all connected loads simultaneously when the primary source fails.

In many scenarios, nonselective ABTs are utilized in applications where maintaining power to all systems is critical and there isn't a need to prioritize some systems over others. This is particularly relevant in environments like hospitals or data centers, where power is essential and all loads may need to be energized quickly, regardless of their priority.

The other types of ABTs mentioned in the choices might include features that allow for priority switching or selective loads based on certain criteria, and thus they do not fit the definition of being nonselective. Understanding these distinctions is crucial for applications where power reliability and distribution are the primary concerns.