CableDataSheet, Cable and Wire Technical Consulting Service

Clearance for installation

Clearance is the distance between the top of the uppermost cable in the conduit andthe inner top surface of the conduit. It should be at least 10% of the conduit innerdiameter or one inch for large cables or installations involving numerous bends.Equations for calculating clearance (CL) are presented as follows:

For single cable

CL=D-d

For three cables, triplexed, triangular(E-24)

CL=D/2-1,366*d+(D-d)/2*(1-(d/(D-s))^2)^0,5

For three cables, cradles

CL=D/2-d/2+(D-d)/2*(1-(d/(D-s))^2)^0,5

where:

D= conduit inner diameter, in inches
d= cable outer diameter, in inches

When calculating clearance, ensure all cable diameters are equal. If in doubt, use thetriplexed configuration equation. The cables may be single or multiple-conductorconstruction