# Depth of laying

The depth of laying is defined as:

• center axis for directly buried cables or heat sources
• center of the duct/tunnel for cables in ducts/tunnel
• center of the group for cables/ducts in trefoil formation
• at the middle on the bottom of the trough

With the deep burial thermal inertia option activated, $L_{cm}$ is replaced with $L_{deep}$.

Symbol
$L_{cm}$
Unit
m
Formulae
$\frac{L_c}{1000}$
Related
$L_c$
$L_{deep}$
Used in
$D_{dry}$
$d_f$
$d_{psc}$
$d_t$
$\Delta \theta_{e,t}$
$\Delta \theta_{sun}$
$L_{deep}$
$L_{dry}$
$R_{q22}$
$s_{b3}$
$T_e$
$\tau$
$z_{earth}$