ICC Residential Electrical Inspectors Practice Exam

What is the maximum allowable ampacity for conductors exposed to a maximum temperature of 60 degrees Celsius?

1. 75 amperes

2. 85 amperes

3. 90 amperes

4. 95 amperes

The correct answer is: 75 amperes

The maximum allowable ampacity for conductors exposed to a maximum temperature of 60 degrees Celsius is 75 amperes. This specific rating is significant as it aligns with the National Electrical Code (NEC) requirements, which provide guidance on the safe carrying capacity of electrical conductors based on their temperature rating. Conductors are rated for various temperatures, and factors such as insulation type, environment, and continuous load must all be considered. The ampacity of 75 amperes corresponds to conductors with a temperature rating of 60 degrees Celsius, specifically for conductors with certain insulation types like THW or THWN, which are appropriate for specific applications and conditions. Understanding this concept is essential for ensuring safe electrical installations and preventing overheating, which can lead to insulation damage and increased risk of fire. Familiarity with these temperature definitions helps in selecting the right conductor for a given application, especially in residential electrical systems where safety is paramount.