Electrical Exam Term

Voltage Drop

The reduction in voltage along a conductor due to its inherent resistance, which increases with conductor length and current flow.

Detailed Explanation

While the NEC does not mandate maximum voltage drop, it recommends (in informational notes) a maximum of 3% for branch circuits and 5% combined for feeders and branch circuits. Excessive voltage drop causes equipment to operate inefficiently, lights to dim, and motors to overheat. The formula for single-phase voltage drop is: Vd = (2 × K × I × D) / CM, where K is the resistance constant, I is current, D is distance, and CM is the circular mil area of the conductor.

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Practice QuestionEasy

Which of the following best describes the concept of Voltage Drop?

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