A cathodic protection system uses electricity to prevent metal structures like pipelines from corroding. The system creates an electrochemical cell using the corrosive metal as the cathode, with a sacrificial metal acting as the anode to collect corrosion.
If you have a cathodic protection system in place, it’s a good idea to test it every two to four years. There are a few types of cathodic protection testing equipment the specialist may use; let’s look at how each of them works.
Copper Sulfate Half-Cell
This piece of equipment is also called a portable reference electrode. When the cathodic protection specialist tests your CP system, they will insert the copper sulfate half-cell partway into the soil and connect it to a voltmeter. Reference electrodes are used to define a constant potential when measuring cathodic protection.
A voltmeter that gives readings in small measurements, like milliamps, is an indispensable tool for testing cathodic protection. The voltmeter connects to both the anode and the cathode to test how well the CP system is protecting the cathode from corrosion.
Selectable Input Resistance Digital Multimeter
Cathodic protection analysts use a couple of different types of multimeters when testing CP systems. A multimeter with selectable input resistance allows the specialist to test the resistance of the circuit that keeps your pipes from corroding.
High Impedance Digital Multimeter
Resistance and impedance, while often used interchangeably, refer to different elements of a cathodic protection circuit. A high impedance digital multimeter measures the opposition of the flow of a current through a conductor. This tool is especially handy when dealing with the soil around the CP system, as soil resistivity can contribute to inaccurate readings.
Soil Resistivity Meter
Speaking of soil, cathodic protection experts need to know how the ground itself conducts electricity in order to get accurate CP readings. A soil resistivity meter uses probes stuck in the ground at regular intervals to measure how strongly it resists electrical current activity.
If your pipeline’s cathodic protection system is due for an inspection, call Dreiym Engineering to enlist the expertise of certified professionals. Our simple, direct approach utilizes several types of cathodic protection testing equipment and years of firsthand experience in the field.