Cable size calculator
Find the minimum cable section so the voltage drop stays under the allowed limit (usually 3 % for lighting, 5 % for motors). Enter the current, the line length and the maximum percentage; the tool suggests the next standard section.
- Minimum section
- 3.31 mm²
- Recommended standard section
- 4 mm²
Indicative result: always verify against the standards and the installation method on site.
Formula
S = (k × ρ × L × I × cos φ) / ΔU (k = √3 three-phase, 2 single-phase)
Good to know
- Based on voltage drop; also check the current-carrying capacity (heating) for the installation method.
- ρ ≈ 0.0225 Ω·mm²/m for copper, 0.036 for aluminium.