Cableizer ®

Equivalent diameter conductor

This equation somewhat underestimates the equivalent diameter of sector-shaped conductors that are not solid.

An alternative approach for multi-core cables with sector-shaped conductors would be to set the equivalent diameter equal to the nominal diameter of a round conductor with the same cross-sectional area. This would still only be an approximation, since the exact degree of compaction of sector-shaped conductors can vary and depends on manufacture. Also, nominal diameters are not available for all cross-sectional areas of conductors and we extrapolated the missing values.

For sector-shaped conductors, CIGRE TB 880 Case study 10 recommends to use the smallest typical conductor diameter as given in IEC 60228 or analogue American standard for AWG/kcmil conductors.

Symbol
$d_x$
Unit
mm
Formulas
$2\sqrt{\frac{A_c}{\pi}}$round conductors
$2\sqrt{\frac{A_c}{\pi}}+t_i$sector-shaped conductors
$\operatorname{min}\left(d_c\right)$sector-shaped conductors CIGRE TB 880 Case study 10
Related
$A_c$
Cross-sectional area conductor [mm$^2$]
$d_c$
External diameter conductor [mm]
$\pi$
Archimedes' constant $\pi$
$t_i$
Thickness insulation [mm]
Used in
$d_{c,t}$
External diameter conductor, transient [mm]
$G_1$
Geometric factor $G_1$
$r_c$
Radius conductor [mm]
$r_{isc}$
Radius above the inner semi-conducting layer [mm]
$s_c$
Separation of conductors in a system [mm]
$X_K$
Factor $X_K$
$Y_K$
Factor $Y_K$
$y_p$
Proximity effect factor conductor