What does a megohmmeter measure?

A megohmmeter measures insulation resistance, which is crucial in assessing the integrity of electrical insulation within cables, motors, transformers, and other electrical devices. This instrument applies a high voltage to the insulation material and measures how much current leaks through it. The result is expressed in megohms, hence the name "megohmmeter."

Insulation resistance is vital because it helps ensure that the insulation can effectively prevent unintended current flow, which could lead to short circuits, equipment damage, or electrical shocks. By evaluating insulation resistance, technicians can determine whether the insulation is intact or if it has deteriorated, necessitating repair or replacement.

This specific measurement differentiates a megohmmeter from devices that measure current flow, voltage levels, or circuit continuity. Those measurements focus on different electrical characteristics and functionalities, making insulation testing a unique and critical task for safety and operational efficiency in electrical systems.