# Element B of equivalent thermal circuit

In the case of cables in air, the transient temperature rise of conductor above outer surface is obtained by replacing $T_B$ by $(T_B+T_C)$.

Symbol
$T_{B}$
Unit
K.m/W
Formulae
 $T_{2_{1}} q_{2_{1}} + T_{2_{2}} q_{2_{2}} + T_{4ii} q_{4} + q_{3} \left(T_{3} + T_{4i}\right)$ long-term transients $\frac{T_{1}}{2} + T_{2_{1}} q_{2_{1}} + T_{2_{2}} q_{2_{2}} + T_{4ii} q_{4} + q_{3} \left(T_{3} + T_{4i}\right)$ short-term transients $T_{B} + T_{C}$ cables in air
$T_{1}$
$T_{2_{1}}$
$T_{2_{2}}$
$T_{4i}$
$T_{4ii}$
$T_{C}$
$N_{0}$
$Q_{B_{ab1}}$
$Q_{B_{ab2}}$
$Q_{B_{d}}$
$Q_{B_{f}}$
$Q_{B_{i}}$
$Q_{B_{j}}$
$Q_{B_{s}}$
$T_{a0}$
$T_{b0}$