What is the allowable voltage drop for branch circuits according to the NEC?

The National Electrical Code (NEC) sets guidelines to ensure that electrical systems are safe and efficient. For branch circuits, the allowable voltage drop is typically set at 3%. This limit is essential to prevent excessive voltage loss that could cause equipment to operate inefficiently, leading to potential failures or safety hazards.

In addition, feeders, which are the conductors that carry power from the service equipment to the branch circuits, have a slightly higher permissible voltage drop of 5%. This reflects the fact that feeders generally handle larger loads and might have longer lengths compared to branch circuits, allowing for a bit more flexibility in voltage drop without adversely affecting performance.

The combination of 3% for branch circuits and 5% for feeders ensures that the overall voltage drop remains within acceptable limits for safe and effective operation of electrical systems, which aligns with the guidelines tested in this practice exam.