Does the sacrificial anode metal of the water cooler need to be insulated from the metal being protected?

Find the answer! Let the experts explain! Looking forward to it!

This post was last edited by henry07010 on 2015-7-17 09:00. Cathodic protection comes in two forms: sacrificial anode protection and impressed current cathodic protection. 1. Sacrificial anode cathodic protection involves connecting a metal with a more negative potential to the metal to be protected, and placing them in the same electrolyte; this allows electrons from the sacrificial metal to transfer to the metal being protected, thereby putting the entire protected metal at a similar, more negative potential. This method is simple and easy to implement; it requires no external power supply and causes little corrosion interference. It is widely used to protect metal structures that are small in size (with a current generally less than 1 ampere) or located in environments with low soil resistivity (soil resistivity less than 100 ohms·meter). 2. External current cathodic protection involves the use of an external direct-current power supply and a auxiliary anode to supply a large number of electrons to the metal, thereby putting the entire protected metal in a state of electron excess. This ensures that all points on the metal surface reach the same negative potential, resulting in the electrical potential of the protected metal structure being lower than that of the surrounding environment. This method is mainly used to protect large metal structures or those located in soil with high electrical resistivity, such as long-distance buried pipelines and large groups of tanks. If a sacrificial anode method is used to protect the water cooler, the sacrificial anode must be connected to the water cooler; otherwise, even if they are insulated from each other, no protection will be provided. What you are seeing is likely a combined protection method that uses coating insulation for corrosion prevention along with a sacrificial anode; using insulation for the inner or outer surface of the water cooler tubes helps to reduce the amount of sacrificial anodes needed. The insulating coating provides its own level of protection, and together with cathodic protection, this results in dual protection. A coating layer is applied to the metal surface and used in combination with cathodic protection (i.e., so-called dual protection). The coating layer isolates the metal from the surrounding medium, preventing large-scale corrosion and essentially enabling control over overall corrosion ； The cathodic current generated by the cathodic protection system flows into the pinholes and various defects in the coating layer, thereby controlling the corrosion that could occur in these weak areas and providing corrosion protection ； Moreover, the presence of the coating layer reduces the current required for cathodic protection by orders of magnitude compared to that required for bare metal, thereby lowering energy consumption and costs.

OP, have you considered using an insoluble anode? These days, there are also many water heaters that use insoluble anodes