What does the term "megger" refer to in electrical testing?

• A. An instrument used to measure current flow
• B. A device used to measure insulation resistance
• C. A tool for connecting wires
• D. A tester for voltage output

Answer: (B)

The term "megger" refers specifically to a device used to measure insulation resistance in electrical systems. Insulation resistance is crucial for ensuring that electrical systems operate safely and efficiently. A megger applies a high voltage (typically between 100V to 1000V) to the insulation of electrical cables or components and measures how well the insulation resists electrical flow. This measurement helps to identify potential insulation failures or degradation that could lead to short circuits, equipment damage, or electrical shocks.

In the context of electrical testing, understanding the role of insulation resistance is vital. High insulation resistance indicates good insulating properties, while low resistance could signal a problem. This makes the megger an invaluable tool in maintenance and commissioning processes, ensuring safety and reliability in electrical installations.