5.3.2 Sacrificial Anode Systems
Sti-P3 tanks that are equipped with a pre-installed sacrificial anode system and test station must be tested within six (6) months of installation and at least once every three (3) years thereafter until the tank is ten (10) years old. Testing must be once every year thereafter.
A typical test setup for a sacrificial anode system is shown in the diagram to the right. The reading on the voltmeter must be equal to or greater than -850 millivolts (mV) with a 100 mV instant-off potential with respect to a saturated copper / copper sulfate half-cell placed in the electrolyte (e.g. soil).