NEC Commercial Electrical Practice Test

What is the maximum rating for a cord-and-plug connected portable appliance used in a 20-amp branch circuit?

1. 20 amps

2. 12 amps

3. 16 amps

4. 10 amps

The correct answer is: 16 amps

In the context of the National Electrical Code (NEC), when considering portable appliances that are cord-and-plug connected and used on a 20-amp branch circuit, the maximum rating of the appliance is crucial for safety and efficiency. The code sets guidelines on the load that can be safely connected to a branch circuit without risking overload. The correct answer is based on a common practice where a device should not exceed 80% of the branch circuit's rating to allow for continuous loads. For a 20-amp circuit, this allows a safe maximum load of 16 amps (20 amps x 0.8 = 16 amps). This limit ensures that the circuit can safely handle the load while preventing overheating and potential hazards. Thus, selection of a cord-and-plug connected appliance indeed up to 16 amps keeps the operation within safe parameters on a 20-amp circuit, which aligns with NEC recommendations for continuous loads. This understanding is vital for both compliance with electrical standards and maintaining safe working conditions.