HOLT Electricians Complete Practice Exam 2025

The correct answer is that the branch circuit conductor for fixed electric space heating equipment loads must be no smaller than 125 percent of the total load. This guideline is established to ensure that the conductors can safely handle the maximum expected load without overheating or risking circuit failure.

When considering fixed electric space heating loads, there is a need for additional capacity to account for potential variations in the load due to ambient temperature changes or other environmental factors. By specifying 125 percent, the NEC (National Electrical Code) ensures that the conductor has enough ampacity to manage momentary overloads and to maintain operation within safe limits over time.

Using a percentage greater than 100 allows for a safety margin that enhances the reliability and longevity of the electrical system, which is essential given the continuous operation of heating equipment. Lower percentages, such as 100%, would not provide this necessary buffer, potentially leading to overheating and failure of the conductor during peak load conditions.