Cathodic Protection Tester Practice Exam

What is the required minimum potential difference for cathodic protection in a structure?

1. 80 mV

2. 100 mV

3. 120 mV

4. 150 mV

The correct answer is: 100 mV

The required minimum potential difference for effective cathodic protection in a structure is 100 mV. This threshold is established based on standard practices for ensuring that a structure, such as a pipeline or storage tank, is properly protected from corrosion. The 100 mV potential difference indicates that the structure is effectively polarized and receiving sufficient cathodic protection from the rectifier or anodes used in the system. The selection of this potential value is critical since a lower potential may not provide adequate protection against corrosion, allowing for the possibility of metal loss and leading to premature failure of the structure. The 100 mV level ensures that the electrochemical reactions that cause corrosion are sufficiently inhibited. Understanding this threshold is essential for professionals working in the field of cathodic protection, as it forms a benchmark for assessing the effectiveness of protection systems in place.