Accurate monitoring of cathodic protection relies upon the proficiency of the test personnel and the proper operation of the required equipment. The equipment consists of properly insulated test leada, an electronic voltmeter with a known internal circuit resistance, and a reference electrode. The proper operation of each piece of equipment is critical to the accuracy of the cathodic protection test results. However, the reference electrode ia not often suspected of being responsible for unexpected cathodic protection readings. This paper will provide
background on the use of portable reference electrodes and data used to evaluate the performance of buried reference electrodes installed adjacent to a single, catholically protected, underground storage tank. Data accumulated at the test site clearly indicates that not all buried reference electrodes provide identical results. Keywords: buried reference cell (BRC), cathodic protection (CP), copper/copper sulfate electrode (CSE), half-cell potential measurement, reference electrode, underground storage tank (UST)