Inventors:
Robert M. Speck - Richmond TX
Assignee:
Westinghouse Electric Corp. - Pittsburgh PA
International Classification:
G01N 2742
Abstract:
An apparatus for measuring cathodic protection voltage levels on a concealed conductive structure, includes a probe having a standard half cell reference electrode, a working electrode and an auxiliary electrode mounted in a fixed spacial relationship to each other, wherein the reference electrode, working electrode and auxiliary electrode are each in contact with an electrolytic solution. A voltage measuring device is provided for receiving a voltage from said reference electrode. The voltage measuring device provides an indication of the voltage difference between the reference electrode and a common reference point. A switch is included for connecting and disconnecting the working electrode with the common reference point. A voltage detecting circuit detects voltage between the concealed conductive structure, which is subject to a cathodic protection voltage, and the common reference point. A bias voltage is applied to the auxiliary electrode in response to the voltage level between the concealed conductive structure and the common reference point.