Patent 7317321 was granted and assigned to NTG on January, 2008 by the United States Patent and Trademark Office.
A method for testing effectiveness of a cathodic protection device configured to apply at least one voltage across an underground structure and a reference point is described. The method includes providing a sample of the material from which the underground structure is fabricated, placing the sample proximate the underground structure, electrically connecting the sample to the underground structure through a switch, operating the switch at predetermined intervals, and measuring electrical characteristics of the sample at intervals based at least partially on the predetermined intervals and a position of the switch.