Calculate the required cable cross-section according to DIN VDE 0298-4 and DIN VDE 0100-520. Considers cable length, voltage, current, installation type and material (copper/aluminium).
Fill in the fields below and click "Calculate".
Cable Cross-Section Calculator
Determine the correct cable cross-section for your electrical installation quickly and reliably. Our calculator uses DIN VDE 0298-4 and DIN VDE 0100-520 to give you accurate results.
How to Use
Enter the current type, voltage, current strength, cable length and installation type. The calculator instantly shows the required minimum cross-section.
Why Correct Cable Sizing Matters
- Prevents overheating and fire hazards
- Ensures compliance with DIN VDE standards
- Optimises energy efficiency
- Required for installation approvals
Current-carrying capacity by cross-section (copper)
These are the values the calculator uses (copper, three loaded conductors, 30 °C ambient, no grouping), based on the German standard DIN VDE 0298-4. Other countries apply their own tables (e.g. IEC 60364-5-52, BS 7671, NEC) – always check local regulations.
| Cross-section | In conduit | Surface-mounted | Buried |
|---|---|---|---|
| 1.5 mm² | 13.5 A | 17.5 A | 19 A |
| 2.5 mm² | 18 A | 24 A | 26 A |
| 4 mm² | 24 A | 32 A | 35 A |
| 6 mm² | 31 A | 41 A | 45 A |
| 10 mm² | 42 A | 57 A | 61 A |
| 16 mm² | 56 A | 76 A | 82 A |
| 25 mm² | 73 A | 96 A | 104 A |
| 35 mm² | 89 A | 119 A | 125 A |
Maximum cable length at 3 % voltage drop
Same formula as the calculator: L = γ × A × ΔV ÷ (2 × I × cos φ), with √3 instead of 2 for three-phase; copper γ = 56 m/(Ω·mm²), cos φ = 1, ΔV = 3 % of nominal voltage. The current-carrying capacity above must also be sufficient.
| Application | Current | Cross-section | Max. length |
|---|---|---|---|
| Socket circuit 230 V | 16 A | 2.5 mm² | 30 m |
| Cooker circuit 230 V | 20 A | 2.5 mm² | 24 m |
| EV charger 11 kW, 400 V | 16 A | 2.5 mm² | 61 m |
| EV charger 11 kW, 400 V | 16 A | 4 mm² | 97 m |
| EV charger 22 kW, 400 V | 32 A | 6 mm² | 73 m |
| EV charger 22 kW, 400 V | 32 A | 10 mm² | 121 m |
These values are a planning aid. Installation must comply with local wiring regulations and be carried out or checked by a qualified electrician.
