Electrical Tools

Voltage Drop Calculator

Calculate voltage drop for electrical circuits and feeders. Ensures compliance with NEC recommendations of 3% for feeders and 5% total.

Circuit Parameters

Voltage Drop Analysis

Voltage Drop 0%
Voltage at Load 0V
Actual Voltage Drop (V) 0 V
NEC Recommendation 3%
Status -
Recommended Wire Size -
Power Loss (Watts) 0 W
Annual Energy Loss $0

NEC Guidelines

  • Feeders Only: Max 3% drop
  • Branch Only: Max 3% drop
  • Feeder + Branch: Max 5% total
  • FPN: Informational only

Formula (Single Phase)

VD = (2 × K × I × D) ÷ CM

Where:

K = 12.9 (Cu) or 21.2 (Al)

I = Current (amps)

D = Distance (one-way)

CM = Circular Mils

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