By continuing to browse this website or by clicking 'I Accept', you agree to the use of cookies. Cookies are stored on your computer or mobile device and enhance your site experience. To learn more about how we use cookies, you can click the 'Learn More' button.
Deciding which cable insulation to use for impressed current anodes depends on installation parameters. A single layer of HMWPE insulation is a good choice for anodes but is not chemically resistant. Therefore, the insulation can deteriorate when exposed to certain chemicals, such as chlorine gas, causing premature cable failure. Adding a primary layer of Halar provides a very chemically resistant protective layer to the copper cable. It is the best choice when significant chlorine gas is produced in the anode well and in contact with anode cable.
Most Cathodic Protection (CP) technicians understand the purpose and operating features of CP rectifiers. However, when the CP system goes down, troubleshooting a CP rectifier may require some help.
The following provides a basic understanding of the function of the CP rectifier and some basic troubleshooting tests that can identify many of the common rectifier problems.
The following are considerations when selecting the type of cathodic protection (CP) system for a newly installed, existing buried or submerged structure.
Surface Area of Exposed Metal The size and cost of most CP systems are controlled by how much CP current is required to effectively protect the exposed metal in contact with the electrolyte (soil or water). Therefore, one of the first considerations when designing or selecting a CP system is the surface area of metal exposed to the electrolyte.
In the corrosion industry, “coupons” are used in the fight against corrosion, but the term coupon is used interchangeably in corrosion monitoring. In fact, there are two general types of corrosion monitoring coupons used for entirely different purposes.
Cathodic Protection Coupons These metallic coupons of a specific size are used to assess the effectiveness of cathodic protection (CP) systems. They are typically made of the same metal as the structure being protected. CP coupons are buried adjacent to the structure under protection, and a coupon cable or cables are routed to an above-ground test station where CP professionals can conduct CP testing. The CP coupon, which is bare metal, represents a coating defect or “holiday” in the structure’s protective coating
During a typical cathodic protection (CP) field survey, the CP technician must make effective electrical connections to the structure under test and other metallic components.
Often, the technician will encounter an existing above-ground test station where a conductor (cable) is permanently attached to the structure under test and the other end is terminated to the test station panel. In this case, the connection to the structure is already made and is typically effective.
When an existing CP system requires review and/or testing, the work will be to determine if the system is working correctly and/or to troubleshoot system issues. Before the fieldwork starts, it is important to review any available documentation or historical data describing the type of CP equipment and itsperformance.
Electrical isolation for buried or submerged pipelines is crucial for cathodic protection and the overall operational integrity of the pipeline. Effective electrical isolation can provide many technical advantages for pipeline operators.
Cathodic protection prevents corrosion of pipelines, storage tanks, and other critical buried or submerged infrastructure assets that support our daily lives. When used effectively, cathodic protection (CP) and coatings are the best methods for preventing subsurface corrosion.
The Use of Wire in Cathodic Protection In the Cathodic Protection (CP) industry, as with many others, we use a vast assortment of electrical devices with significant variations of operating ranges. For instance, reference electrodes operate at less than one volt with currents measured in micro-amps. At the same time, large CP power supplies can have system voltages exceeding 450 volts and up to 1,000 amperes of DC output. These electrical devices all utilize wire of varying sizes and operating requirements, and the wire sizes can be small as 0.01” (10 thousandths) diameter to over 0.46” diameter.
