Cathodic Protection Tester Practice Exam

What is not suitable for testing resistance between structures in a corrosive environment?

1. Ohmmeters

2. Ammeter

3. Multimeter

4. Voltmeter

The correct answer is: Ohmmeters

The use of an ohmmeter for testing resistance between structures in a corrosive environment is not suitable because ohmmeters require direct contact with the conductive paths being measured. In corrosive environments, this contact can lead to erroneous readings due to surface corrosion or effects from the environment, which may impact the accuracy and reliability of the measurements. Additionally, ohmmeters may not appropriately account for the presence of stray currents or other influencing factors typical in these environments. In contrast, other instruments like ammeters, multimeters, and voltmeters can be used more effectively under such conditions. Ammeters can measure current in a circuit without needing direct contact with the structure's surface, and multimeters can be versatile depending on their configuration. Voltmeters can also measure potential difference without requiring direct contact, which can help to avoid the issues associated with corrosion. Thus, while all instruments have their specific applications, an ohmmeter's method of measurement makes it less suitable for assessing resistance in this context.