Journeyman Electrician Practice Exam 2025 - Free Electrician Practice Questions and Study Guide

When calculating the minimum rating of the overcurrent protection device for feeder conductors supplying a continuous load, it's essential to reference the National Electrical Code (NEC) guidelines. According to NEC Article 210.20 and 240.4, the standard requirement is to size the overcurrent protection device to be at least 125% of the continuous load.

In this case, the continuous load is 240 amperes. To determine the minimum required rating for the overcurrent protection device, you would perform the following calculation:

1. Calculate 125% of the continuous load:

\( 240 \, \text{amperes} \times 1.25 = 300 \, \text{amperes} \)

The minimum rating of the overcurrent protection device should therefore be 300 amperes. This ensures that the device can safely handle the continuous load without tripping under normal operating conditions.

Choosing a rating lower than 300 amperes, such as 200 or 250 amperes, would not comply with the NEC's requirement to protect the system adequately. Selecting a rating higher than 300 amperes, such as 350 amperes, is permissible but not necessary, as it exceeds the minimum requirement for this specific