Cableizer ®

Temperature rise ratio

Ratio of cable or duct outside surface temperature rise above ambient to the conductor temperature rise above ambient under steady-state conditions.

Symbol
$k_{t}$
Unit
p.u.
Formulas
$\frac{\theta_{de}-\theta_{a}}{\theta_{c}-\theta_{a}}$
Related
$\theta_{a}$
Ambient temperature [°C]
$\theta_{c}$
Temperature conductor [°C]
$\theta_{de}$
Temperature duct outer surface [°C]
Used in
$M_{1}$
Corrected cyclic rating factor [K]
$\theta_{R}$
Rated current transient to steady-state ratio