Oklahoma Electrical Practice Exam

What is the smallest value of the load that can be used to calculate branch circuits for incandescent signs?

1. 15 amperes

2. 20 amperes

3. 25 amperes

4. 30 amperes

The correct answer is: 20 amperes

The correct choice reflects the minimum load requirement for calculating branch circuits specifically for incandescent signs. According to the National Electrical Code (NEC) guidelines, when sizing branch circuits for lighting loads, including incandescent signs, a minimum load of 20 amperes is typically utilized. This standard is set to ensure that the circuit can handle the electricity demand of the load effectively while providing a safety margin to account for potential increases in load over time. Choosing a smaller amperage, such as 15 amperes, may not provide sufficient capacity for the circuit, leading to potential overloads if the actual load exceeds this rating. Similarly, the higher values like 25 or 30 amperes, while acceptable for different applications, exceed the minimum requirement and do not specifically address the smallest allowable load for this context. Thus, 20 amperes stands as the smallest value that meets the regulatory standards and practical considerations for safety and performance in branch circuit calculations for incandescent signage.