Max. conductor temperature

Values for maximum conductor temperature depending on the insulation material for normal operation, under emergency overload operation (max 8 hours/day and 100 hours/year) and during short-circuit are according to IEC 60840 and IEC 62087 where available with the following additions:

Values for Polypropylene (PP) are taken from the book 'Handbook of Electrical Engineering: For Practitioners in the Oil, Gas and Petrochemical Industry' by A.L. Sheldrake (2003)
Values for Silicone rubber (SiR) as well as EVA, ETFE, FEP, PTFE and PFA are taken from Leoni LEOMER 'Insulation material properties'
High temperature materials SiR and EVA are limited to 100°C and extra-high temperature materials ETFE, FEP, PTFE and PFA are limited to 110°C.

The IEC 60724 defines the short-circuit temperature limit of PVC at 160°C for cables with cross-section ≤ 300mm$^2$ and at 140°C for cables with cross-section > 300mm$^2$

The temperatures for emergency overload have been reduced beginning of 2023.

Symbol

$\theta_{cmax}$

Unit

°C

Related

$M_i$

Material of insulation

$\theta_{cmaxeo}$

Max. emergency overload conductor temperature [°C]

$\theta_{cmaxsc}$

Max. short-circuit conductor temperature [°C]

$\theta_{kf}$

Final temperature [°C]

Used in

$\Delta \theta_{max}$

Maximum permissible conductor temperature rise [K]

$\Delta \theta_{R,\infty}$

Maximum permissible conductor temperature rise [°C]

$\Delta W$

Incremental heat generated [W]

Choices

Material	Normal operation	Emergency overload	Short-circuit
PE	70	80	130
HDPE	80	90	160
XLPE	90	105	250
XLPEf	90	105	250
PVC	75	90	160
EPR	90	105	250
IIR	85	105	250
PPLP	70	80	130
Mass	80	95	150
OilP	80	95	150
PP	80	95	150
SiR	100	130	225
EVA	100	130	180
ETFE	110	130	230
FEP	110	150	260
PTFE	110	150	305
PFA	110	150	290