The rating factor Cd is applied to cable sizing calculations for cable installed in the ground. Its value varies according to the depth of lay installed. See BS7671:2018,Table4B4.
Indicates the depth of installation for cables installed in the ground. The rating factor Cd is applied in cable sizing calculations to account for different installation depths.
For cables with Installation Methods 70 to 73, values of Cd are found in BS7671:2018,Table 4B4.
For methods using BICCdata, rating factor Cd has a value of 1.0 for a depth of 0.5m. For greater depths the value of the rating factor will be less than 1,and greater than one for shallower depths.