HOLT Electricians Practice Exam

What is the minimum ampacity percentage required for branch circuit conductors to a single motor based on the motor's full load current?

1. 100 percent

2. 125 percent

3. 150 percent

4. 200 percent

The correct answer is: 125 percent

The minimum ampacity percentage required for branch circuit conductors supplying a single motor is set at 125 percent of the motor's full-load current. This requirement is in place to ensure that the conductors can handle not only the normal operating current of the motor but also any potential overload conditions that may occur during startup or operation. Motors typically draw significantly more current during starting than during normal operation, and accounting for this ensures both safe operation and protection against overheating of the conductors. By using 125 percent, the calculations provide an additional margin, which is crucial for the longevity and reliability of both the motor and the circuit. This standard helps prevent excessive voltage drop, potential circuit damage, and ensures that the circuit can accommodate variations in the load efficiently. Essentially, the code requires this percentage to guarantee sufficient conductor sizing for safety and performance, aligning with industry best practices for electrical installations.