Three-Phase Voltage Drop Calculator (Balanced Feeder)
Commercial building electrical design, manufacturing plant motor feeder sizing. Computes exact line-to-line voltage loss across balanced 3-phase commercial feeder conductors in steel or PVC conduit.
Step-by-Step Derivation ▼ Show Steps
Calculations adhere to standard electrical engineering physics and National Electrical Code (NFPA 70) regulations.
Engineering Principles & Calculations
This calculator uses the exact mathematical relationships between Line Current (Amps), Line-to-Line Voltage (208V, 400V, 480V, 600V), Conductor Size (AWG/kcmil), Length (ft/m), Conduit Material (Steel/PVC/Aluminum) to determine Voltage Drop (Volts), Percentage Drop (%), End-of-Line Voltage (V). In practical installations, factors such as ambient raceway temperature, harmonic distortion, duty cycle continuous operation, and conductor impedance must be accounted for by a certified electrician.
Computes exact line-to-line voltage loss across balanced 3-phase commercial feeder conductors in steel or PVC conduit.
Typical Application & Industry Guidelines
Commercial building electrical design, manufacturing plant motor feeder sizing.
Three-Phase Voltage Drop Calculator (Balanced Feeder) Benchmark Lookup Table
| Feeder Amps | Wire Gauge (Cu) | Distance (ft) | Drop @ 480V 3-Phase | Drop @ 208V 3-Phase |
|---|---|---|---|---|
| 50 Amps | #4 AWG Copper | 150 Feet | 0.83% (4.0V) | 1.92% (4.0V) |
| 65 Amps | #4 AWG Copper | 250 Feet | 1.80% (8.7V) | 4.17% (8.7V - FAIL) |
| 100 Amps | #1 AWG Copper | 200 Feet | 1.11% (5.3V) | 2.56% (5.3V) |
| 150 Amps | 2/0 AWG Copper | 250 Feet | 1.31% (6.3V) | 3.02% (6.3V) |
| 200 Amps | 4/0 AWG Copper | 300 Feet | 1.32% (6.3V) | 3.04% (6.3V) |