Oklahoma Electrical Practice Exam

What is the maximum over current protection for a branch circuit supplying a single non-motor operated utilization equipment rated at 20 amps?

1. 15 amps

2. 20 amps

3. 25 amps

4. 30 amps

The correct answer is: 20 amps

The maximum overcurrent protection for a branch circuit supplying a single non-motor operated utilization equipment rated at 20 amps is determined based on the National Electrical Code (NEC) guidelines. According to NEC regulations, the overcurrent protection device (typically a circuit breaker or fuse) should be rated at 125% of the equipment's maximum load for continuous loads or at the equipment’s rated load for non-continuous loads. In this specific scenario, since the equipment is rated at 20 amps and it is not a motor, the maximum overcurrent protection should match the equipment rating, which is 20 amps. This allows for safe operation without risking equipment damage while providing the necessary protection for the circuit. Selecting a rating higher than 20 amps, such as 25 amps or 30 amps, could result in excessive current flowing through the equipment, which could lead to overheating and potential failure. Therefore, using the exact rating of 20 amps aligns with the code requirements and ensures that the equipment can operate safely and effectively.