# Conduit clearance

The clearance in the duct is the distance between the top of the uppermost cable in the conduit and the inner top surface of the conduit. It should be at least 10% of the conduit inner diameter or 1/4 inch (6.35 mm). Cableizer will provide a warning if this is not the case.

For larger cables or installations with multiple bends, the clearance should be up to 1 inch (25.4 mm). Cableizer cannot be held responsible for insufficient clearance! But generally, clearance should not be a problem when respecting the maximum conduit fill $CF_{pull}$ limits.

The conduit clearance is calculated for up to four cables depending on their configuration.

Symbol
$CC_{pull}$
Unit
mm
Formulas
 $Di_d-D_e$ 1 cable $Di_d-2D_e$ 2 cables $\frac{Di_d}{2}-1.366D_e+\frac{Di_d-D_e}{2} \sqrt{1-\left(\frac{D_e}{Di_d-D_e}\right)^2}$ 3 cables (triangular) / 4 cables (cradled) $\frac{Di_d-D_e}{2}+\frac{Di_d-D_e}{2} \sqrt{1-\left(\frac{D_e}{2\left(Di_d-D_e\right)}\right)^2}$ 3 cables (cradled) $Di_d-D_e-\frac{2{D_e}^2}{Di_d-D_e}$ 4 cables (diamond)
Related
$D_e$
$Di_d$