Dielectric strength

Dielectric strength is the resistivity of insulators to electrical sparkover. The value is highly dependent on the material thickness, and this must consequently also be specified.

These factors influence the dielectric strength

  • Type of electrodes and applied voltage
  • Thickness, homogeneity and moisture content of the specimen
  • Type of environment (medium, temperature, pressure, etc.)


In the case of plastics filled with carbon black, particular care over the dielectric strength must be taken for thin-walled components, as carbon black can substantially reduce the dielectric strength of a plastic.