In the absence of alternative formulae, it is recommended that the formulae should be used for sector and oval-shaped conductors.

Symbol
$y_{\mathrm{s}}$
Unit
-
Formulae
$\frac{x_{\mathrm{s}}^{4}}{0.8 x_{\mathrm{s}}^{4} + 192}$$x_{\mathrm{s}} \leq 2.8$
$0.354 x_{\mathrm{s}} - 0.733$$x_{\mathrm{s}} > 3.8$
$0.0563 x_{\mathrm{s}}^{2} - 0.0177 x_{\mathrm{s}} - 0.136$otherwise
$\frac{x_{\mathrm{s}}^{4}}{0.8 x_{\mathrm{s}}^{4} + 192}$GIL
Related
$x_{\mathrm{s}}$
$R_{\mathrm{0}}$