What device is used to measure high resistance in cables?

The device used to measure high resistance in cables is a megohmeter. This instrument specifically measures resistance values in the megaohm range, which is essential for testing the insulation resistance of electrical cables. High resistance measurements are crucial for determining the health and integrity of wiring insulation, especially in applications where moisture, dirt, or other contaminants could lead to breakdowns or leakage currents.

A megohmeter applies a high voltage to the insulation being tested, which allows it to detect any potential weaknesses or failures in the insulation. It provides a clear reading of how well the insulation is performing under stress, making it a preferred choice for linemen and electricians when assessing cable conditions.

Devices like an ohmmeter are designed for lower resistance measurements and would not be suitable for assessing the insulation of cables where much higher resistance values are expected. A cable tester may check for various parameters, but it does not specifically focus on high insulation resistance. Similarly, a voltmeter measures voltage rather than resistance, making it inadequate for this purpose. Hence, the megohmeter stands out as the appropriate tool for measuring high resistance in cables.