Potential measurement interpretation on isolating joints

Interpretation of potential measurements on isolating joints can be complicated by internal interference from a conductive electrolyte, for example salt water, in hydrocarbons. The on-off technique, carried out by means of a high-frequency data logger voltmeter, permits detection of corrosion caused by such interference. A case history exemplifies the principle and the interpretation of the measurement. The method is a simple and effective one to determine internal interference.