Cathodic protection polarization potential - 850mv criterion

According to this criterion, when the polarization potential of the structure relative to the copper / saturated copper sulfate reference electrode is at least - 850mv, it can be fully protected. Polarization potential means the potential at the interface of structure / electrolyte, which is the sum of corrosion potential and cathodic polarization value.


This code is mainly applied to coated structures which can cut off DC power supply. It is very difficult to cut off all power supply and sacrificial anode for gas pipeline. Therefore, the advantages and disadvantages of this criterion are very prominent.


Compared with other methods, the polarization potential-0.85 V (CSE) criterion has the following advantages:

① The voltage drop error caused by protection current has been eliminated;

② It is mainly applicable to the coated structure which can cut off the DC power supply.



The disadvantages are:

① It needs a lot of equipment and is laborious and laborious;

② If there is stray current, or the sacrificial anode is directly connected to the structure, or there is external forced current equipment and cannot be interrupted, the result is very uncertain;

③ Due to the influence of measurement method, season, test point, coating condition of structure surface, earth current effect and medium condition, there are also error problems.