The potential across a tubesheet under cathodic protection can show large variations from one location to another. Different waterboxes of the same apparent design can produce different potential distributions. Areas with excessively electronegative potentials can cause hydrogen damage to titanium or ferritic stainless steel tubes. Other areas may have potentials insufficiently negative to adequately protect the copper alloy tubesheet. These potential gradients cannot be detected by a reference electrode mounted on the side wall of the waterbox.

The Model TE Tubesheet Mounted Reference Electrode is designed to mount any place on the face of a tubesheet. They are shipped with a double tube plug which is inserted into the end of a condenser tube and tightened. Tube plugs are available for common tube sizes between 5/8 inch and 1-1/4 inch. The electrode's lead wire terminates in a waterproof connector which plugs into a mating connector on the Model TW wire which has been affixed to the tube sheet face. This attachment system allows the electrode to be easily removed during scheduled outages.