<p>A method of monitoring the protection delivered to steel bars (1) in concrete construction protected by a discrete sacrificial anode cathodic protection system comprising measuring potentials at potential measurement points located at close intervals in a representative area while the installed sacrificial anodes (2) are operating wherein the potential measurement points include at least three points (3) all located between but away from the same nearby installed anodes (2) and are all preferably located between the same pair of adjacent parallel steel bars. The results are used to identify the position of local anodes. The identification of anodes at locations where none are installed indicates that the steel may not be protected and the discrete sacrificial anode cathodic protection system is not operating effectively.</p>
