Nominal voltage includes a range of actual circuit voltages that are:

Nominal voltage refers to a standard or target voltage that defines the expected operating voltage for electrical systems. It is not just a single value but rather encompasses a range of actual circuit voltages that can fluctuate due to various factors such as load conditions, temperature, and manufacturing tolerances.

Choosing the option that indicates both above and below the nominal voltage recognizes that actual voltages in a circuit can vary, meaning that they can indeed exceed the nominal level or fall below it, while still functioning within the acceptable limits for performance and safety. This understanding is crucial for electrical professionals to ensure proper equipment selection, system design, and maintenance.

In contrast, options that limit the range to being only less than the nominal voltage or exclusively equal to it overlook the essential nature of electrical systems, where variances are commonplace. Additionally, stating that voltages are exactly equal to the nominal voltage ignores the inherent variability in real-world applications, which is important for professionals to consider when working with electrical systems.