ICC Residential Electrical Inspectors Practice Exam

What is the maximum rating allowed for any one cord and plug connected utilization equipment supplied by a 15 amp branch circuit?

1. 60%

2. 80%

3. 100%

4. 50%

The correct answer is: 80%

The maximum rating allowed for any one cord and plug connected utilization equipment supplied by a 15 amp branch circuit is 80%. This guideline is based on the National Electrical Code (NEC) rules which recommend that the continuous load on a circuit should not exceed 80% of its rated capacity to ensure safety and prevent overheating of the wiring and equipment. In this case, a 15 amp branch circuit allows for a maximum continuous load of 12 amps (15 amps x 0.80 = 12 amps). This limit is in place to account for situations where the equipment could be used for extended periods, thus reducing the risk of circuit overload. Such a precaution helps in the overall safety of the electrical installation, preventing possible fire hazards and ensuring that the circuit operates within safe limits. Choices suggesting different percentages, such as 60%, 100%, and 50%, do not align with the accepted safety standards for continuous loads on branch circuits, where 80% is the recognized maximum to allow for safe operation and mitigate risks associated with prolonged usage.