Calculateur de Filtre Harmonique
Calculez les paramètres d'un filtre harmonique pour votre installation.
3-5 for enclosed, 5-8 for open air
For temperature, grouping, etc.
Derated Ampacity
24.0 A
Derated Ampacity vs Conductor Cross Section
Formule
## 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.
Exemple Résolu
6 mm^2 copper cable, 5 A/mm^2, derating 0.8, at 230 V.
- 01Base ampacity: 6 x 5 = 30 A
- 02Derated: 30 x 0.8 = 24 A
- 03Max power: 24 x 230 = 5,520 W = 5.52 kW
Questions Fréquentes
Is this a substitute for NEC/IEC tables?
No. This provides estimates. Always use the applicable electrical code tables for final cable sizing in real installations.
What happens if I exceed ampacity?
The cable overheats, insulation degrades, and eventually a fire hazard develops. Overcurrent protection (breakers/fuses) should prevent this.
How does cable length affect sizing?
Longer cables have more resistance, causing voltage drop. You may need to upsize the cable beyond ampacity requirements to limit voltage drop.
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