NCCER Industrial Maintenance Electrical & Instrumentation (IME&I) Practice Exam

An insulation resistance tester is commonly referred to as a megohmeter. This instrument is specifically designed to measure the resistance of electrical insulation, providing readings in megohms (millions of ohms). The primary function of a megohmeter is to assess the integrity of insulation in wiring systems and equipment by applying a high voltage to ensure that the insulation can withstand operational conditions and prevent electrical leaks or failures.

This device operates by generating a specific voltage that tests the resistance of lighting, wiring, or electrical devices, which helps identify potential insulation breakdowns that could lead to safety hazards or equipment malfunction. In contrast, the other instruments listed serve different purposes: a multimeter can measure voltage, current, and resistance but does not specialize in high-voltage insulation testing; an ohmmeter measures resistance but typically at much lower voltage levels; and a voltmeter measures electrical potential difference without assessing the quality of insulation. Understanding the specific applications of these tools is crucial for effective maintenance and troubleshooting in industrial settings.