Plumbers Teflon tape is 0.0010 inches thick. Teflon's dielectric strength is 6500 volts per 0.001 inch for a 0.001 inch thick film. The dielectric strength is not proportional to film thickness. At 0.002 inch thick, its value is 5,000 volts per 0.001 inch. At 0.010 inch thick, its value is 2,500 volts per 0.001 inch. Regards, Steve WA2TAK