Understanding Voltage Drop: The Complete Guide
What is Voltage Drop?
Voltage drop is the reduction in electrical potential (voltage) that occurs as electric current flows through a conductor. This phenomenon is a fundamental principle in electrical engineering, governed by Ohm's Law, which states that voltage equals current multiplied by resistance (V = I × R).
Understanding voltage drop is essential for every electrical professional. Proper voltage drop calculations ensure that equipment receives adequate power, systems operate efficiently, and installations comply with the National Electrical Code (NEC) recommendations.
Key Principle
Every conductor has resistance. When current flows through this resistance, voltage is "dropped" across the conductor according to Ohm's Law: V = I × R.
NEC Voltage Drop Recommendations
Maximum recommended voltage drop from the panel to the final outlet.
Combined maximum for both feeder and branch circuit from the service entrance.
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