The HVIRM 5000 is a 5kV Diagnostic Insulation Tester (often called a megohmmeter or megger) is a diagnostic tool used to measure the electrical insulation resistance of cables, motors, transformers, switchgear, and other high-voltage equipment. By applying a controlled DC voltage (up to 5,000 volts), it checks whether the insulation is deteriorating, contaminated, or failing — all of which can lead to dangerous breakdowns.