How long does a load have to be on, to be considered continuous load?

• A. 1 hour
• B. 2 hours
• C. 3 hours
• D. 4 hours

Answer: (C)

Continuous load means a load that is expected to run for an extended period, specifically three hours or more. This 3-hour threshold matters because sustained operation can cause heat buildup in conductors and equipment, so engineers size conductors and protective devices with that extra margin in mind. In practice, any load that runs for three hours or longer is treated as continuous. That means a load lasting three hours is continuous, and a load lasting longer—like four hours—is also continuous. Loads that run for less than three hours aren’t considered continuous. So the minimum duration to be treated as continuous is three hours.