Electrical Engineering
Minimum Conductor Cross-Section
Calculate the minimum required conductor cross-section to stay within a maximum permissible voltage drop, for 1-phase or 3-phase AC and DC circuits.
Units:
Always choose the next standard size above the calculated minimum. Standard sizes: 0.5 | 0.75 | 1.0 | 1.5 | 2.5 | 4 | 6 | 10 | 16 | 25 | 35 | 50 mm². Also verify the selected cable is rated for the current (ampacity).
A_min (1-ph) = 2×ρ×L×I×cos(φ) / ΔU | A_min (3-ph) = √3×ρ×L×I×cos(φ) / ΔU
Input
Cable length (one way) iOne-way cable length in metres.
m
Current I iMaximum current through the cable in Ampères.
A
Max. voltage drop ΔU iMaximum permissible voltage drop in Volts. IEC 60364: 3% = 6.9V at 230V (lighting), 5% = 11.5V (motors).
V
Power factor cos φ iPower factor of the load.
System i1-phase AC, 3-phase AC or DC circuit.
Result
Minimum cross-section [mm²]
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Recommended standard size [mm²]
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Cable resistance (std size) [Ω]
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Actual voltage drop (std size) [V]
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