# Thermal resistivity of insulation

The values of the thermal resistivity of insulation are taken from standard IEC 60287-2-1 Ed.2.0 where available with the following additions:

• For the purposes of current rating calculations, the semi-conducting screening materials are assumed to have the same thermal properties as the adjacent dielectric materials.
• Value for Polypropylene (PP) is based on the minimal value of thermal conductivity (0.17 to 0.22) given in the book 'Polypropylene - The Definitive Users Guide and Databook', Plastics Design Library, 1998. whereas a range of 0.10 to 0.23 is given by professionalplastics.com
• Value for Silicone rubber (SiR) is taken from shinetsusilicone-global.com
• Value for Ethylene vinyl acetate (EVA) is taken from expresspolymlett.com and J. Allan and Z. Dehouche: 'Enhancing the thermal conductivity of ethylene-vinyl acetate (EVA) in a photovoltaic thermal collector', 2016 ().

Symbol
$\rho_i$
Unit
K.m/W
Related
$U_n$
Used in
$T_1$
$T_i$
$T_{ins}$
$T_{is}$
Choices
MaterialValue
PE3.5
HDPE3.5
XLPE3.5
XLPEf3.5
PVC5.0 (U_n <= 3kV)
6.0 (U_n > 3kV)
EPR3.5 (U_n <= 3kV)
5.0 (U_n > 3kV)
IIR5.0
PPLP5.5
Mass6.0
OilP5.0 (self-contained)
5.0 (pipe-type oil-filled)
5.5 (pipe-type gas pressure)
PP5.9
SiR5.0
EVA4.35