Introduction to PE insulated cables

Polyethylene is a semi-crystalline polymer available in a wide variety of versions with differing chemical structures, molecular weights and densities determined by the various methods of polymerisation.

All polyethylenes have excellent dielectrics - high dielectric strength, low dielectric constant, and low dissipation factor at all frequencies. This makes it an ideal insulation across a range of different cable types including telephone and high speed transmission, high frequency signal and control cable, low,  medium and high voltage power cables, overhead line wire and service drop cables.

Whilst PE naturally has poor fire resistance it can be significantly improved by the addition of fillers – both halogenated types or halogen free types. PE can also be compounded to include additives which enhance other properties such as resistance to sunlight, weathering and chemical degradation. PE is a hard and abrasion-resistant material which makes it useful as a sheathing material in various applications but where a more flexible material is required the addition of small amount of butyl or ethylene propylene rubber (EPR) can improve flexibility. The toughness of the PE also makes it suitable for direct burial in the ground.

The temperature range is typically -65°C to +75°C but cross-linking the polyethylene (to make XLPE) can extend this temperature range to +90°C.