The fast switching times of Wide Bandgap (WBG) devices pose a challenge for the insulation design of voltage source inverter (VSI)-fed motors, interturn insulation in particular. This paper discusses interturn insulation breakdown problem due to steep fronted voltage at motor terminals and calculates the electrical stress for different insulations in a motor based on the standards IEC 60034-18-42 and IEC 60034-18-41. IEC TS 61800-8 is used to estimate voltage appearing at the terminals of motor in an electric drive installation so that the insulation can be designed accurately. With Silicon Carbide (SiC) devices enabling Medium-Voltage (MV) Pulse Width Modulation (PWM) VSI drives for high speed, MW class motors, accurate insulation design is critical for reliability of these motors. This paper uses FEM model to calculate non-uniform voltage distribution in the winding and coil. The contribution of this paper is a comprehensive overview of insulation design for WBG device based converter-fed motors and accurate estimation of increase in insulation volume for random wound and MV form wound motors.