Which component is critical for measuring the effectiveness of a grounding system?

A digital multimeter is a crucial tool for assessing the effectiveness of a grounding system because it can measure various electrical parameters such as voltage, current, and resistance. Specifically, when evaluating a grounding system, the digital multimeter can be used to check the resistance of the ground connection. A low resistance reading indicates a good grounding system, while a higher resistance may indicate potential issues that could lead to electrical hazards or ineffective operations.

In contrast, an amperemeter primarily measures current flowing through a circuit, which is not directly useful for assessing the grounding system's effectiveness. Similarly, a voltmeter measures voltage but does not provide information about the grounding connection's resistance. An oscilloscope is designed for observing the waveform of electrical signals, which is also not directly applicable to measuring ground effectiveness. Therefore, the digital multimeter stands out as the essential instrument for this specific function in evaluating grounding systems.