Cableizer ®

Thickness conductor—sheath, transient

For calculation of the cyclic and emergency current rating of cables acc. IEC 60853, the multi-core cable is replaced by an equivalent single-core construction dissipating the same total conductor losses. The space between the equivalent single-core conductor and the sheath is considered to be completely occupied by insulation. For oil-filled cables, this space is filled partly by the total volume of oil in the ducts and the remainder is oil-impregnated paper.

Symbol
$t_{1,t}$
Unit
mm
Formulas
$t_1$single-core cables
$\frac{D_{i,t}-d_{c,t}}{2}+t_{scb}+t_{scs}+\frac{H_{sh}+\Delta H}{2}$multi-core cables, type SS
$\frac{D_{i,t}-d_{c,t}}{2}+t_{scb}+t_{scs}+t_f+\frac{H_{sh}+\Delta H}{2}$multi-core cables, type SC
$\frac{D_{i,t}-d_{c,t}}{2}+t_f+t_{scb}+t_{scs}+\frac{H_{sh}+\Delta H}{2}$multi-core cables, type CC
$\frac{D_{i,t}-d_{c,t}}{2}+t_{scb}+t_{scs}+t_f$multi-core cables, without screen & sheath
$\frac{D_{i,t}-d_{c,t}}{2}+t_{scb}$pipe-type cables
Related
$d_{c,t}$
External diameter conductor, transient [mm]
$D_{i,t}$
Diameter over insulation, transient [mm]
$\Delta H$
Correction depth of corrugation [mm]
$H_{sh}$
Depth of corrugation [mm]
$t_1$
Thickness conductor—sheath [mm]
$t_f$
Thickness of filler/belt insulation [mm]
$t_{scb}$
Thickness screen bedding [mm]
$t_{scs}$
Thickness screen serving [mm]