The values for the loss factor of insulation are taken from standard IEC 60287-1-1 Ed.2.1 where available with the following additions:

Symbol
$\mathrm{tan}\delta _{\mathrm{i}}$
Unit
-
Related
$M_{\mathrm{i}}$
$U_{\mathrm{n}}$
Used in
$W_{\mathrm{d}}$
Choices
MaterialValue
PE0.001
HDPE0.001
XLPE0.004 (Un <= 30kV)
0.001 (Un > 30kV)
XLPEf0.005
PVC0.1
EPR0.02 (Un <= 30kV)
0.005 (Un > 30kV)
IIR0.05
PPLP0.0014
Mass0.01
Oil0.0035 (Un <= 60kV)
0.0033 (60kV < Un <= 150kV)
0.003 (150kV < Un <= 280kV)
0.0028 (280kV < Un <= 500kV)
PP0.001
SiR0.025
EVA0.022