190 HANDBOOK OF ELECTRICAL ENGINEERING
Table 9.5.Electrical and physical properties of thermoplastic and thermoset resinsas insulatorsPropertyPVCEPRXLPEPPPEPCPCSPPTFEDielectric relative permittivity at50 Hz4 to 73.52.2 to 5.02.252.35—102.0Dielectric strength used forcontinuous service MVrms/m15 kV×25 mm2single core3.53.83.8—4.5———Volume resistivity at 20◦Cohm-m×109102to 1042
×104104to 6×104107107—30 107Loss angle tanδat 50 Hz0.10.0050.0005 max0.00050.0006—0.060.003Temperature in◦Catwhichdistortion or softening occurs12018013012090 to 100—160300Density kg/m31.2 to 1.50.920.95 to 0.97———Tensile strength kg/cm2or N/mm212.0to14.04to812to1837371010to20 22Water absorption Note a)3999934—Conductor maximum continuoustemperature◦C7085 to 90908070 to 757585260Minimum environmentaltemperature◦CZero Note b)−40−50−10−50−10−30—Thermal resistivity Km/W5.54.53.53.55.5——Max conductor temp◦Cfor5secshort circuit IEC 502160250250150130—200300Resistance to heat Note a)59551959Flame retardance Note a)99111899Resistance to acids and alkalisNote a)5(3)9 99859Resistance to mineral oils Note a)51191779Resistance to weather Note a)59571—79Resistance to abrasion Note a)75397773Resistance to ozone Note a)97599—95Emission of acid gas Note a)91————4—Low oxygen index %25 to 3520 to 401818184030 to 4095Note a) 1 denotes poor performance.4 denotes an average performance.9 denotes excellent performance.Note b) For special compounds the minimumtemperature can be as low as 30◦C.