Voltage drop
Estimate feeder voltage drop from resistance, reactance and power factor, using your chosen voltage-drop limit.
Enable JavaScript for live calculations. Read the method and default example below.
Method and assumptions
- ΔV = √3 × I × L × (R cosφ + X sinφ). L is one-way length.
- Indicative hot conductor resistivity: 0.02193 Ω·mm²/m; R = 0.4386 Ω/km; X = 0.08 Ω/km.
- Maximum length at the entered limit: 231 m.
Before using the result
- Use manufacturer resistance and reactance for final design. The entered supply voltage must match the phase arrangement; this estimate does not cover starting transients or unbalanced circuits.
Worked example
Illustrative default inputs. Enter your project values above.
- Load current
- 100 A
- One-way cable length
- 60 m
- Conductor size
- 50 mm²
- Supply voltage
- 415 V
- Supply arrangement
- Three phase — balanced
- Conductor material
- Copper
- Insulation
- XLPE — 90 °C
- Load power factor
- 0.85
- Cable reactance
- 0.08 Ω/km
- Permitted drop
- 4 %
Default results
- Voltage drop
- 4.31 V
- Percentage drop
- 1.04 %
- Entered limit
- Within entered limit
Choose a reference or send your BOQ
Compare relevant product families, then confirm the exact rating, control supply and duty. Price and availability are confirmed with your enquiry.
Technical references
These references support planning. The exact model documentation and a project-specific engineering review govern the final specification.