What is the definition of continuous load in terms of maximum current duration?

The definition of continuous load refers to an electrical load that is expected to operate at or near its maximum current for a prolonged period of time. According to the National Electrical Code (NEC), a continuous load is defined as a load that is expected to operate continuously for three hours or more. This duration is significant because it helps electricians and engineers design electrical systems that can handle the thermal and electrical stress caused by prolonged current flow, ensuring safety and preventing overload conditions.

In contrast, the other options provide durations that do not align with the established definition in the NEC. A load operating for less than three hours does not meet the criteria for classification as continuous, and therefore, it is important to adhere strictly to the three-hour standard in electrical design and safety practices.