Abstract: A method for processing and displaying insulation resistance values in insulation fault monitoring devices for an IT power supply system includes determining an insulation resistance value in predetermined time intervals, detecting an insulation fault if the determined resistance value falls below a preset limit value, showing an optical alarm message if the insulation fault is present, wherein the determined insulation resistance value is time stamped and stored, the time stamp marked as the alarm time upon detection of the insulation fault, after determining and storing n insulation resistance values following the alarm time, a number n of the insulation resistance values determined prior to the alarm time, the insulation resistance value determined at the alarm time and a number n of the insulation resistance values determined after the alarm time are copied into a cache and graphically displayed.