What does a megohmmeter measure?

A megohmmeter is specifically designed to measure insulation resistance in megohms, which is crucial for assessing the integrity of electrical insulation. This tool applies a high voltage to the insulation material, enabling the measurement of resistance to current flow. When the insulation is in good condition, it will exhibit high resistance, typically in the range of megohms. A low reading indicates potential issues with the insulation, such as deterioration or failure, which can lead to electrical shorts or leaks.

In contrast, current is measured in amperes using an ammeter, while voltage is measured in volts with a voltmeter. Power consumption is quantified in watts with a wattmeter. Each of these instruments and measurements serves a distinct purpose in electrical work, but the megohmmeter's unique function focuses on the insulation quality, making it a critical tool for ensuring safety and performance in electrical systems.