What is the required rating for a branch circuit supplying a continuous load?

The requirement for a branch circuit supplying a continuous load is to ensure that the circuit can safely handle the electrical demands without overheating or posing a risk of failure. Continuous loads are defined as loads that are expected to operate for three hours or more.

To accommodate for this, the National Electrical Code (NEC) dictates that the branch circuit must be rated for at least 125% of the continuous load in order to provide a safety margin and prevent the circuit from being overloaded. This is important as electrical systems must be designed to handle potential increases in load and avoid overheating, which can lead to electrical fires or equipment failure.

Thus, when choosing the rating for a branch circuit, it must not only support the continuous load but also account for any additional loads connected to that circuit. Therefore, the correct answer signifies that the rating should encompass both the continuous load and an extra capacity to cover other potential loads, thereby ensuring both safety and compliance with the NEC standards.