What is the recommended maximum voltage drop for feeders and electrical systems according to the NEC?

The National Electrical Code (NEC) recommends a maximum voltage drop of 5% for feeders and branch circuits in residential, commercial, and industrial installations. This standard seeks to maintain the efficiency of electrical systems and ensure that equipment operates effectively without experiencing performance issues associated with excessive voltage drop. A drop beyond this threshold can lead to insufficient power supply to devices, causing them to operate inefficiently or even leading to potential electrical failures.

While there may be discussions about more lenient voltage drop percentages in some contexts, such as lighting circuits, the 5% guideline is a widely accepted standard aimed at providing a balance between safety, performance, and energy efficiency throughout an electrical system. Adhering to this standard helps ensure that the voltage levels remain within acceptable limits, promoting the longevity and consistent performance of electrical appliances and systems.