What function does a "megger" serve?

A "megger," short for megohmmeter, is specifically designed to test insulation resistance in electrical systems, particularly the grounding systems. It measures the resistance of the grounding conductors, which is crucial for ensuring the effectiveness of a lightning protection system and the overall safety of electrical installations. By applying a high voltage to the circuit and measuring the current that flows through the insulation, a megger can determine whether the insulation is adequate and whether there are any faults that could lead to dangerous electrical situations. This makes it an essential tool for verifying proper grounding and ensuring that the resistance is low enough to provide effective protection against lightning strikes and electrical surges.

Other functions listed, such as testing airflow or measuring temperature, do not relate to the primary purpose of a megger, which is focused on electrical resistance and safety within grounding systems. Analyzing voltage levels is also outside the primary function, as the megger is not used to measure operational voltage in circuits. Thus, the correct answer identifies the tool’s specific role in maintaining electrical safety and integrity.