Cable Sizing Calculator
Estimate the minimum cable cross-sectional area based on current capacity requirements.
Minimum Conductor Area
10.0 mm^2
Minimum Conductor Area vs Design Current (I)
Formule
## Cable Sizing by Current Density The cable must carry the required current without exceeding safe temperature limits. ### Simplified Method **A = I / J** where A is the conductor cross-sectional area, I is the design current, and J is the allowable current density. Typical values: enclosed cables 3-4 A/mm^2, open-air cables 5-6 A/mm^2. Always verify against manufacturer ampacity tables and installation derating factors.
Exemple Résolu
40 A load with 4 A/mm^2 allowable current density.
- 01A = 40 / 4 = 10 mm^2
- 02Select the next standard size: 10 mm^2 or 16 mm^2 depending on available sizes.
- 03Also verify voltage drop is within limits for the cable run length.
Questions Fréquentes
What are standard cable sizes?
Common metric sizes: 1.5, 2.5, 4, 6, 10, 16, 25, 35, 50, 70, 95, 120, 150, 185, 240 mm^2. Always round up to the next standard size above the calculated minimum.
What affects cable ampacity?
Installation method (open air, conduit, buried), ambient temperature, number of cables grouped together, insulation type (PVC, XLPE), and conductor material (copper vs aluminium) all affect the maximum safe current.
Should I check voltage drop after sizing?
Yes. Cable sizing must satisfy both thermal (ampacity) and voltage drop criteria. For long runs, voltage drop often requires a larger cable than the thermal calculation alone.
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