Cross-sectional area of filler

Symbol
$A_{f}$
Unit
mm$^2$
Formulae
$0$single-core cables
$\frac{D_{f}^{2} \pi}{4} - 2 \pi \left(\frac{D_{f}}{2} - t_{f}\right)^{2}$two-core cables
$\frac{D_{f}^{2} \pi}{4} - \left(-1.5 + \sqrt{3}\right)^{2} \left(D_{f} - 2 t_{f}\right)^{2} \left(\frac{5 \pi}{2} + \sqrt{3}\right)$three-core cables
$\frac{D_{f}^{2} \pi}{4} - \pi \left(\frac{D_{f}}{2} - t_{f}\right)^{2}$sector-shaped multi-core cables
Used in
$Q_{f}$