Electrical Safety Regulation 2026
sec.279Maximum potential change
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sec.279 Maximum potential change
The owner of a cathodic protection system must ensure the system complies with the requirements of this section. Maximum penalty—40 penalty units. This section states requirements for a cathodic protection system in relation to a foreign structure for the system. The potential change, foreign structure to ground, must not be more than any of the following— at a point 100m radially from an anode, if there is no metallic link between the cathodically protected structure and the foreign structure—150mV in a negative going direction; at a point where buried or submerged parts of the foreign structure are in ground or water generally of 1 ohm metre or higher resistivity—10mV in a positive going direction; at a point where buried or submerged parts of the foreign structure are in ground or water generally below 1 ohm metre resistivity—0mV; for a foreign structure that is not connected electrically to the cathodically protected structure— 500mV in a negative going direction; or with the foreign structure owner’s written agreement—1V in a negative going direction. However, for short-term testing of the cathodic protection system, 5 times the potential change stated in subsection (3) (a) or (b) and twice the potential change stated in subsection (3) (d) is permitted. The potential change stated in subsection (3) (b) or (c) may be changed with the foreign structure owner’s written agreement after an assessment of the effect of any existing cathodic protection or interference mitigation measures on the foreign structure. (sec.279-ssec.1) The owner of a cathodic protection system must ensure the system complies with the requirements of this section. Maximum penalty—40 penalty units. (sec.279-ssec.2) This section states requirements for a cathodic protection system in relation to a foreign structure for the system. (sec.279-ssec.3) The potential change, foreign structure to ground, must not be more than any of the following— at a point 100m radially from an anode, if there is no metallic link between the cathodically protected structure and the foreign structure—150mV in a negative going direction; at a point where buried or submerged parts of the foreign structure are in ground or water generally of 1 ohm metre or higher resistivity—10mV in a positive going direction; at a point where buried or submerged parts of the foreign structure are in ground or water generally below 1 ohm metre resistivity—0mV; for a foreign structure that is not connected electrically to the cathodically protected structure— 500mV in a negative going direction; or with the foreign structure owner’s written agreement—1V in a negative going direction. (sec.279-ssec.4) However, for short-term testing of the cathodic protection system, 5 times the potential change stated in subsection (3) (a) or (b) and twice the potential change stated in subsection (3) (d) is permitted. (sec.279-ssec.5) The potential change stated in subsection (3) (b) or (c) may be changed with the foreign structure owner’s written agreement after an assessment of the effect of any existing cathodic protection or interference mitigation measures on the foreign structure.