FORMULA
Calculation method
Suggested section = max(section satisfying ampacity, section satisfying voltage drop)
As circuit length increases, voltage drop rises and a section adequate for ampacity can become inadequate for voltage drop.
CABLE SELECTION
Cable Size Calculator and Copper Cable Selection Table
Check load current and voltage drop together to estimate the minimum copper or aluminium conductor size.
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CALCULATOR
Copper / aluminium cable pre-selection
Calculated load current28,30 A
Suggested minimum section6 mm²
Drop at this section2,61 %
iThis is a preliminary result. Final selection must check manufacturer data, applicable IEC requirements, installation method, ambient temperature, grouping, harmonics, short-circuit withstand and protection coordination.
DYNAMIC SELECTION TABLE
Current and maximum line length by section
The table updates for your 28,30 A load current and 3% voltage-drop limit.
| Section | Approx. ampacity | Drop at entered length | Approx. maximum length | Status |
|---|---|---|---|---|
| 1.5 mm² | 18 A | %10,33 | 23 m | Insufficient |
| 2.5 mm² | 24 A | %6,22 | 39 m | Insufficient |
| 4 mm² | 32 A | %3,90 | 62 m | Insufficient |
| 6 mm² | 41 A | %2,61 | 92 m | Suitable |
| 10 mm² | 57 A | %1,59 | 151 m | Suitable |
| 16 mm² | 76 A | %1,01 | 239 m | Suitable |
| 25 mm² | 101 A | %0,66 | 364 m | Suitable |
| 35 mm² | 125 A | %0,48 | 498 m | Suitable |
| 50 mm² | 151 A | %0,35 | 686 m | Suitable |
| 70 mm² | 192 A | %0,26 | 917 m | Suitable |
| 95 mm² | 232 A | %0,20 | 1.178 m | Suitable |
| 120 mm² | 269 A | %0,17 | 1.412 m | Suitable |
| 150 mm² | 309 A | %0,14 | 1.664 m | Suitable |
| 185 mm² | 353 A | %0,12 | 1.924 m | Suitable |
| 240 mm² | 415 A | %0,11 | 2.272 m | Suitable |
FREQUENTLY ASKED
About this calculation
Is this result sufficient for ordering cable?
No. Installation method, ambient temperature, grouping, insulation and short-circuit withstand must be checked in final selection.
Why is the table ampacity approximate?
Ampacity depends on cable construction and installation conditions. The tool uses general values for preliminary sizing.
ENGINEERING NOTE
Fast calculation, clear assumptions, correct interpretation
The tools are intended for preliminary assessment and checking. Alongside each result, we explain the formula, assumptions and field conditions that require attention.
Prepared by: Neo Kontrol Otomasyon · Last technical review: July 2026
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