Red Seal Industrial Electrician Practice Exam 2026 - Free Practice Questions and Study Guide

To monitor the insulation resistance of wires, the most appropriate device is a Megger. A Megger, or insulation resistance tester, is specifically designed to measure the resistance of insulation in electrical systems. It applies a high voltage between a conductor and the ground to assess how well the insulation is performing. High insulation resistance indicates good insulation quality, while low resistance can suggest deterioration or damage to the insulation, which might lead to electrical leaks or faults.

On the other hand, an ampermeter measures the current flowing through a circuit, which does not provide any information about insulation quality. A voltmeter measures the potential difference across components but does not evaluate insulation integrity. An oscilloscope visualizes electrical signals over time, suitable for analyzing waveform shapes and signal integrity but not for assessing insulation conditions. Therefore, the Megger is uniquely suited for testing insulation resistance, making it the correct answer in this context.