What is the purpose of a megohmmeter?

A megohmmeter is specifically designed to measure insulation resistance, often under high voltage test conditions. The purpose is to assess the integrity of electrical insulation in equipment and wiring, which is critical for ensuring safety and performance. By applying a high voltage during testing, the megohmmeter can detect deterioration or breakdown in insulation that could lead to failures or hazards in electrical systems. This is particularly important for maintenance and safety checks, as good insulation is essential for preventing electrical leakage and ensuring that the equipment functions correctly without posing risks to users or the environment.

In contrast, devices that measure low resistances typically work at much lower voltages and are focused on different applications, such as checking connections and components. Testing continuity of grounding is done with simpler tools, like a continuity tester, rather than a megohmmeter, which serves a more specialized role. Likewise, measuring capacitance requires a capacitance meter, not a megohmmeter, as capacitance assesses different electrical properties.