ToolnozaENGINEERING TOOL
Cable Size Calculator
Estimate minimum metric cable cross-section for your voltage-drop limit, current, length and conductor temperature.
Cable Size Calculator
FREE ONLINE TOOLSTEP BY STEP
How to use cable size calculator
- Check the input units and assumptions.
- Review the result and example.
IN PRACTICE
Example
Copper, 20°C, DC, 230 V, 20 A, 30 m, 3%: minimum 2.9983 mm²; next listed size 4 mm².
GOOD TO KNOW
Which formula and assumptions are used?
Amin = k × I × ρ(T) × L / (V × limit / 100). Selects a listed metric cross-section for voltage drop only. Ampacity, installation method, insulation, grouping, fault protection and local electrical rules must be checked separately. Not a compliance approval.