Cathodic Protection Tester Practice Exam

When using a digital meter, which terminal is the reference electrode connected to for proper polarity?

1. Positive terminal

2. Negative terminal

3. Common terminal

4. Ground terminal

The correct answer is: Negative terminal

When using a digital meter for cathodic protection testing, the reference electrode must be connected to the negative terminal to ensure proper polarity. The reason for this is based on the standard convention in cathodic protection measurements, where the reference electrode serves as a stabilized point of measurement, typically at a known potential. Connecting the reference electrode to the negative terminal allows the meter to measure the potential of the cathodic protection system in relation to the reference electrode. This setup ensures that the readings reflect the true corrosion potential of the structure being protected. If connected incorrectly to the positive terminal, the readings could be reversed or inaccurate, leading to incorrect interpretations of the cathodic protection effectiveness. In contrast, the common terminal usually serves as a return path for other electrical connections, while the ground terminal may be used for safety and stability in electrical measurements but does not provide the needed reference potential for cathodic protection testing like the negative terminal does. Thus, connecting the reference electrode to the negative terminal is essential for obtaining reliable and accurate readings in cathodic protection applications.