Fluoropolymer is a synthetic insulation and is particularly suitable for the inner insulation of heating elements within underfloor heating cables as it has very good electrical properties, only thin layers are required to provide electrical insulation.
Fluoropolymer insulation can cope with the high temperatures within heating cables without any damage as it has a very high melting point, it’s properties do not start to degrade until it reaches 260 °C. The insulation material is, however, less suitable for use with underlaminate systems. In circumstances where there is a major thermal block the insulation will not fail until the system reaches an exceedingly high temperature that could damage the floor covering in extreme circumstances. Heat Mat recommend an insulation with a much lower melting point for use in these types of system.
Some manufacturer’s also use fluoropolymer insulation as the outer insulation for their heating cables however it is not as proficient at resisting crushing and cutting forces as PVC insulation in these circumstances. If installing cables with fluoropolymer outer insulation that has started to go white where the cable is bent you should contact the manufacturer before proceeding as it is possible the insulation has become weakened.