This is the transient temperature rise of conductor above outer surface caused by ohmic losses. The transient response of a cable circuit to a step function of load current, considered in isolation, that is with the right-hand pair of terminals of the thermal circuit short-cuircuited, is found with the following formula calculating the transient temperature rise of conductor above outer surface. The parameter $W_c$ is the power loss per unit length in a conductor or an equivalent conductor based on the maximum conductor temperature attained. The power loss is assumed to be constant during the transient.

Symbol
$\Delta \theta_{\mathrm{c_{\mathrm{t}}}}$
Unit
K
Formulae
$W_{\mathrm{c}} n_{\mathrm{c}} \left(T_{\mathrm{a0}} \left(1 - e^{- a_{\mathrm{0}} \tau}\right) + T_{\mathrm{b0}} \left(1 - e^{- b_{\mathrm{0}} \tau}\right)\right)$
$n_{\mathrm{c}}$
$T_{\mathrm{a0}}$
$T_{\mathrm{b0}}$
$W_{\mathrm{c}}$
Used in
$\Delta \theta_{\mathrm{t}}$