EPDM & PVC insulation materials

A brief guide to the proper selection of electrical insulation materials...

When selecting a material type for electrical insulation purposes, it is important to not only consider its native electrical insulation properties, but all the properties that will be relevant under the particular conditions for the chosen application. Two good insulating materials are PVC and EPDM, one is a plastic the other a synthetic rubber, both have quite different properties. PVC has a long tradition as an electrical insulation medium. EPDM is also classed as having good dielectric strength, but this is determined greatly by the quantity of carbon black in the batch which can significantly effect its insulation properties. In general, the EPDM has better temperature stability, working unaffected through a wider range than PVC which is affected greatly by thermal loading. Both can be quite UV and ozone stable especially the EPDM. UV stabilisers can be added to PVC to lift its native tolerance to weathering. EPDM is a flexible rubber, slightly denser than PVC, so it will weigh more. PVC can be made flexible with enough plastizicers added to the batch. EPDM does have weaker mechanical strength in general terms than PVC.

Overall, if you require an insulation medium that will withstand high temperature differentials and extreme weather situations, go for the EPDM. If you need a more mechanically robust medium at lower temperatures then PVC may be more suitable.