[en] The electrical insulation system to be used for the TF and PF Coils for the TFTR machine will be a vacuum-impregnated epoxy resin and fiberglass laminate. The results of voltage-breakdown endurance tests performed on a large number of specimens are presented. These specimens were fabricated using various processing methods and material formulations to evaluate their effects on the quality and performance characteristics of the insulation. Results for specimens fabricated wth the addition of KAPTON (polyimide) film into the glass-epoxy laminate are also presented. These test results established the probable scatter band of the voltage-endurance characteristics used for the coil designs. 5 refs