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TPS/PVC cables in contact with polystyrene products

TPS/PVC cable insulation can be compromised by a chemical reaction if it is in contact with polystyrene. Make sure you check the insulation is undamaged before installing this cable and always follow the cable manufacturer’s instructions.

The plasticiser in cable insulation make’s the cable flexible, this plasticiser will slowly leach out of the cable over time. The process of cable losing plasticisers can be increased when the cable is in contact with other materials, such as polystyrene and polyurethane. The leaching of the plasticiser will cause the cable’s PVC material to become harder, more brittle and prone to cracking. This could mean live conductors will be exposed, and possibly result in electric shock or fire. It is advisable for consumers to check with the supplier of the polystyrene or polyurethane products for further details as to their suitability around PVC cabling.

One significant factor that affects the rate of leaching is the size of the contact area between the cable and polystyrene. The larger the contact area, the quicker the rate of plasticiser leaching out. The rate of the cable’s deterioration will vary with the installation conditions.

It may mean that the cable becomes unsafe to work near during maintenance, repairs or building alterations, meaning that the cable may need to be replaced sooner than expected.

Typical installations where cabling was used in conjunction with polystyrene products are:

  • caravans
  • cold rooms
  • transportable buildings
  • wall or roofing insulation material.

New installations

Select a cable with protective sheath material that the manufacturer confirms can be installed in contact with materials such as polystyrene and polyurethane. Alternatively cables should be installed so there is no direct contact between the cable and polystyrene.

If installing cables that haven’t been proven suitable for direct contact with polystyrene or polyurethane, either:

  • install the cable in a suitable conduit
  • leave an air gap between the cable and the polystyrene
  • apply a suitable barrier between the cable and the polystyrene.

Existing installations

If you are conducting work in an area where you identify a cable in contact with materials such as polystyrene and polyurethane, check to see if the cable has become hard and brittle. If it hasn’t become hard or brittle, consider actions to remove the contact. If the cable has become hard and brittle, replace it.

Electrical Safety Office
1300 362 128

Last updated
10 November 2017

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