# Convection factor

Coefficient for convection to air, which is an experimentally determinded constant for heat transfer by convection from the cable surface to the air. The values in the standard for vertical and horizontal spacing are equal and thus not repeated here.

The standard does not give values for 2 cables. It was assumed that the values are identical to 3 cables.

Symbol
$K_{cv}$
Used in
$T_{sa}$
Choices
IdValueInstallationRemark
10.1301 cable
20.1153 cables spaced (spacing > 2D)equal for horizontal and vertical spacing
30.0863 cables touching (spacing ≤ 2D)equal for horizontal and vertical spacing
40.0703 cables touching trefoil