📝 How it works:
Calculate the thermally required minimum conductor cross-section during a short circuit per IEC 60364-4-43 (adiabatic, S=√(I²·t)/k).
Fill in the fields below and click "Calculate".
Calculate the thermally required minimum conductor cross-section during a short circuit per IEC 60364-4-43 (adiabatic, S=√(I²·t)/k).
Fill in the fields below and click "Calculate".
During a short circuit the conductor must be large enough not to exceed its permissible limit temperature within the disconnection time. IEC 60364-4-43 gives the adiabatic equation S ≥ √(I²·t) / k.
k is the material factor: copper/PVC 115, copper/XLPE 143, aluminium/PVC 76, aluminium/XLPE 94 (A·s0.5/mm²). I is the effective fault current, t the disconnection time.
Example: I = 1000 A, t = 0.2 s, copper/PVC → S = √(200000)/115 = 3.89 mm² → next standard size 4 mm². This covers short-circuit withstand only; current-carrying capacity (IEC 60364-5-52) must be verified separately – the larger value governs.
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