What is the recommended maximum voltage drop percentage across feeders and branch circuits?

What is the recommended maximum voltage drop percentage across feeders and branch circuits?

• A. 2
• B. 3
• C. 5
• D. 7.5

Answer: (C)

Voltage drop is the loss of voltage that happens as current flows through the resistance of conductors. If a run is long or the conductor is undersized, the end point can see noticeably less voltage than at the source, which can cause lights to dim or equipment to run poorly. The recommended maximum across feeders and branch circuits is 5%. This limit helps ensure the farthest loads still receive enough voltage for proper operation. In practice, designers often aim for about 3% drop for feeders and bring the total (feeders plus branch circuits) to no more than 5%. If the distance or load would push the drop beyond 5%, you’d increase conductor size, shorten the run, or otherwise adjust the design to maintain acceptable voltage at the load.

Voltage drop is the loss of voltage that happens as current flows through the resistance of conductors. If a run is long or the conductor is undersized, the end point can see noticeably less voltage than at the source, which can cause lights to dim or equipment to run poorly.

The recommended maximum across feeders and branch circuits is 5%. This limit helps ensure the farthest loads still receive enough voltage for proper operation. In practice, designers often aim for about 3% drop for feeders and bring the total (feeders plus branch circuits) to no more than 5%. If the distance or load would push the drop beyond 5%, you’d increase conductor size, shorten the run, or otherwise adjust the design to maintain acceptable voltage at the load.