Cable Calc Formula May 2026
[ I = \sqrt\frac\theta_max - \theta_ambR_dc \cdot \left(1 + \alpha(\theta_max - 20)\right) \cdot \left( R_th \right) ]
For AC circuits:
[ I_sc^2 \cdot t = \kappa^2 \cdot S^2 \cdot \ln\left(\frac\theta_f + \beta\theta_i + \beta\right) ] cable calc formula
: [ S_min = \frac25,000 \cdot \sqrt0.2143 \approx \frac25,000 \cdot 0.447143 \approx 78 , mm^2 ] 185 mm² >> 78 mm² — thermal withstand OK. [ I = \sqrt\frac\theta_max - \theta_ambR_dc \cdot \left(1
Simplified (common form):
[ I = \sqrt\frac\theta_max - \theta_ambR_dc \cdot \left(1 + \alpha(\theta_max - 20)\right) \cdot \left( R_th \right) ]
For AC circuits:
[ I_sc^2 \cdot t = \kappa^2 \cdot S^2 \cdot \ln\left(\frac\theta_f + \beta\theta_i + \beta\right) ]
: [ S_min = \frac25,000 \cdot \sqrt0.2143 \approx \frac25,000 \cdot 0.447143 \approx 78 , mm^2 ] 185 mm² >> 78 mm² — thermal withstand OK.
Simplified (common form):
