NCCER IME&I Practice Exam 2025 – All-in-One Guide for Excelling in Industrial Maintenance Electrical & Instrumentation!

A megohmmeter, also known as an insulation resistance tester, is specifically designed to measure the resistance of electrical insulation in circuits and equipment. In the context of electrical maintenance, its primary function is to assess the integrity of insulation materials to ensure that they are effectively preventing unwanted current leakage, which can be detrimental to system safety and performance.

When using a megohmmeter, a high DC voltage is applied across the insulation being tested, and the resulting current flow is used to calculate insulation resistance in megohms. A higher resistance value indicates better insulation quality, while lower values may signal insulation breakdown or deterioration, which can lead to electrical faults or hazards.

Employing a megohmmeter is crucial for preventive maintenance, as it helps identify potential problems before they result in significant failures or downtime. It is essential for ensuring the reliability and safety of electrical systems and equipment.