New York State Master Electrician Practice Exam

A fixed storage type water heater of 120 gallons or less is considered a continuous load. What percentage of the nameplate current rating should the branch circuit conductors have?

1. 100%

2. 110%

3. 125%

4. 150%

The correct answer is: 125%

In this scenario, a fixed storage type water heater with a capacity of 120 gallons or less is classified as a continuous load. According to the National Electrical Code (NEC), when determining the necessary capacity for branch circuit conductors servicing continuous loads, the conductors must be sized based on a percentage of the nameplate current rating of the equipment. For continuous loads, the NEC requires that conductors must be rated at 125% of the continuous load. Therefore, the correct answer is based on this requirement, indicating that the branch circuit conductors should be rated to handle 125% of the nameplate current rating to ensure safety and prevent overheating under continuous operation conditions. This sizing is crucial in maintaining compliance with code and ensuring the longevity and reliability of electrical systems. The other percentages provided do not align with the NEC requirement for continuous loads; hence, they are not suitable choices in this context. Understanding this guideline is essential for Master Electricians when designing and installing circuits for equipment like water heaters.