How is insulation resistance typically measured?

Insulation resistance is typically measured using an insulation resistance tester or megohmmeter. This specialized device applies a high voltage to the insulation of electrical equipment to determine the resistance of that insulation. The measurement obtained is expressed in ohms, specifically in megohms for most applications. This testing method is crucial for assessing the integrity of electrical insulation, helping to identify potential breakdowns or leakage paths that could lead to hazards such as electrical shock or equipment failure.

Other methods listed are not suitable for this type of measurement. A standard multimeter, while useful for measuring resistance, does not supply the high voltage necessary to accurately assess insulation quality. Visual inspection can help identify visible wear and tear but cannot provide concrete data about the insulation resistance itself. A continuity tester is typically used for checking if a circuit is complete but does not test insulation resistance effectively as it does not apply the required voltage.