Hole diameter: 11mm(8) With bakelite cover and cable gland protector 3. Connection Please kindly note that Delta connection CANNOT be switched to either Star-Delta connection or Star connection.Star-Delta connection and Star connection CAN be switched to each other.4. Installation5. Flanged Heater ApplicationsFlanged heaters allow the flexibility of using many different alloys to help resist corrosion and maintain life longevity of the flanged heating element Steel flanges are typically used