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Voltage Drop Calculator
Estimate cable voltage drop for DC, single-phase AC, or balanced three-phase AC circuits.
Your estimate
Enter measurements and select Calculate.
How this estimate works
Use manufacturer resistance at the expected operating temperature, and AC resistance/reactance for AC. Length is one-way; do not double it. DC drop = 2 × I × L × R. Approximate AC drop = factor × I × L × (R × PF + X × √(1 − PF²)), with L in km and factor 2 for single phase or √3 for balanced three phase. Assumes equal conductors, one conductor per phase, and a lagging load. Does not select wire size, ampacity, protection, or certify code compliance.
ABB electrical installation handbook · voltage drop
Values are rounded only for display. Calculations stay on this device. No signup required.
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