Cathodic Protection Tester Practice Exam

Compared to zinc anodes, what advantage do magnesium anodes have?

1. They are cheaper

2. Higher current delivery in high soil resistivity

3. Longer lifespan

4. Less weight

The correct answer is: Higher current delivery in high soil resistivity

Magnesium anodes are particularly advantageous in high soil resistivity conditions because they can provide a higher current output compared to zinc anodes. This heightened current delivery is crucial for effective cathodic protection, as it ensures that sufficient protection is maintained even in environments where resistivity is increased, which could potentially limit the flow of current. Magnesium's electrochemical characteristics allow it to be more effective in these conditions, enhancing its performance where oxidation resistance is required. The focus on high current delivery is essential, as this capability directly influences the efficiency of the cathodic protection system. Effective cathodic protection is vital to prevent corrosion in buried or submerged structures, making the ability of magnesium anodes to perform well in challenging soil conditions a significant advantage over zinc anodes in specific applications.