For voltage measurement in a pipe-to-soil potential profile, the voltmeter should be connected how?

In a pipe-to-soil potential measurement, the goal is to assess the difference in potential between the buried pipeline and the surrounding electrolyte (usually soil). The correct connection method for the voltmeter is to connect it positively to the pipe and negatively to the electrolyte.

When the voltmeter is connected in this manner, it measures the electrochemical potential of the pipe in relation to the surrounding environment. This method provides an accurate representation of the potential felt by the pipe concerning the soil, which is crucial for evaluating corrosion risk and ensuring the effectiveness of cathodic protection systems.

Connecting the voltmeter negatively to the pipe or in any other configuration would not yield a proper potential reading, potentially resulting in reversed or misleading data that does not accurately reflect the pipe's condition compared to the soil's electrochemical environment.