The absorption coefficient of solar radiation for the cable surface is used to calculate the temperature rise due to solar radiation.

The coefficient is material-dependant. Typical values for different cable jacket materials are given in standard IEC 60287-1-1 Ed.2.1. and values for duct materials they are given in standard IEC 60287-2-1 Ed.2.0.

No reference values were found for Polypropylene (PP), Silicone rubber (SiR) and Chlorosulphonated polyethlyene (CSM) and they are assumed to be similar to PVC.

Symbol
$\sigma_{\mathrm{sun}}$
Unit
-
Used in
$\Delta \theta_{\mathrm{sun}}$
Choices
MaterialCablesDucts
PE0.40.4
HDPE0.40.4
PVC0.60.6
PP0.60.6
POC0.6n.a.
SiR0.6n.a.
CR0.8n.a.
CSM0.6n.a.
CJ0.8n.a.
RSP0.8n.a.
BIT0.80.8
Metaln.a.0.3
Fibren.a.0.6
Cemn.a.0.75
Earthn.a.0.75