# Sheath factor

When the losses in the sheats are not equal for a cable system, their inequality affects their external thermal resistance.

Symbol
$f_{SHF}$
Formulae
 $\frac{\frac{\lambda_{12}}{2} + \frac{\lambda_{13}}{2} + \lambda_{2} + \lambda_{3} + 1}{\lambda_{11} + \lambda_{2} + \lambda_{3} + 1}$ phase 1 $\frac{\frac{\lambda_{11}}{2} + \frac{\lambda_{13}}{2} + \lambda_{2} + \lambda_{3} + 1}{\lambda_{12} + \lambda_{2} + \lambda_{3} + 1}$ phase 2 $\frac{\frac{\lambda_{11}}{2} + \frac{\lambda_{12}}{2} + \lambda_{2} + \lambda_{3} + 1}{\lambda_{13} + \lambda_{2} + \lambda_{3} + 1}$ phase 3 $\frac{\frac{\lambda_{12}}{2} + \frac{\lambda_{13}}{2} + 1}{\lambda_{11} + 1}$ GIL, phase 1 $\frac{\frac{\lambda_{11}}{2} + \frac{\lambda_{13}}{2} + 1}{\lambda_{12} + 1}$ GIL, phase 2 $\frac{\frac{\lambda_{11}}{2} + \frac{\lambda_{12}}{2} + 1}{\lambda_{13} + 1}$ GIL, phase 3