Function of insulation monitoring: acoustical and optical warning. Measures the electrical resistance between earth and phase of the consumer. Built-in in the generator.
According IEC 60364-7-717 to use mobile generators in vehicles in EU member states.
If there is an insulation failure active there´s the possibility of an acoustic reset by pressing the acoustic confirmation button. The optical warning is still active until the failure has gone! If the defect item gets disconnectet the insulation failure is resetted automatically.