Cable Ampacity Rechner — Formel
## Cable Ampacity Estimation
Ampacity is the maximum continuous current a conductor can carry without exceeding its temperature rating.
### Formula
**Ampacity = Cross Section x Current Density x Derating Factor**
### Current Density Guidelines
- Open air: 5-8 A/mm^2
- In conduit: 3-5 A/mm^2
- Underground: 2-4 A/mm^2
### Derating Factors
- Ambient temperature above 30 C: 0.7-0.9
- Multiple cables in conduit: 0.5-0.8
- Direct burial: 0.7-0.85
Always verify with NEC/IEC tables for your specific installation.
Ampacity is the maximum continuous current a conductor can carry without exceeding its temperature rating.
### Formula
**Ampacity = Cross Section x Current Density x Derating Factor**
### Current Density Guidelines
- Open air: 5-8 A/mm^2
- In conduit: 3-5 A/mm^2
- Underground: 2-4 A/mm^2
### Derating Factors
- Ambient temperature above 30 C: 0.7-0.9
- Multiple cables in conduit: 0.5-0.8
- Direct burial: 0.7-0.85
Always verify with NEC/IEC tables for your specific installation.
Lösungsbeispiel
6 mm^2 copper cable, 5 A/mm^2, derating 0.8, at 230 V.
- Base ampacity: 6 x 5 = 30 A
- Derated: 30 x 0.8 = 24 A
- Max power: 24 x 230 = 5,520 W = 5.52 kW