Diameter over insulation for transient calculations

This is used for transient calculation acc. IEC 60853 when considering an equivalent conductor for multi-core cables.

Symbol
$D_{it}$
Unit
mm
Formulae
$d_c+2\left(t_i+t_{shj}\right)$Multi-core cables, sector-shaped conductors
$F_x \left(d_c+2\left(t_i+t_{shj}\right)\right)$otherwise