This is the temperature rise above ambient at the surface of the p^{th} cable, whose rating is being determined, caused by the power dissipated by the other (q - 1) cables in the group. The term $\Delta\theta_{pp}$ is excluded from the summation. The influence of touching cables or ducts, as well as cables or ducts from the same cable system, is exluded from the summation.

For cables in air, $\Delta\theta_p$ is 0.

$\Delta \theta_{\mathrm{p}}$

K

$\sum\limits_{k=1}^q \Delta\theta_{\mathrm{kp}}$

$I_{\mathrm{c}}$

$\theta_{\mathrm{c}}$

$\theta_{\mathrm{e}}$

$\theta_{\mathrm{hs}}$

$W_{\mathrm{hs}}$