In electrical installations, earthing systems play a fundamental role in ensuring personal safety and equipment protection. However, a discreet phenomenon can significantly compromise their long-term reliability: the formation of galvanic couples<\/strong>. This electrochemical reaction, still insufficiently considered during design, can lead to accelerated corrosion of buried conductors and earth electrodes. Understanding this risk is essential to ensure durable and compliant earthing systems.<\/p>\n<\/div> A galvanic couple<\/strong> occurs when two dissimilar metals<\/strong> are in electrical contact within a conductive environment<\/strong>, such as moist soil, concrete, or water. The greater the potential difference between the two metals, the faster and more severe the galvanic corrosion.<\/p>\n Common problematic combinations include:<\/strong><\/span><\/p>\n Earthing networks are particularly exposed because they often combine different materials while being permanently in contact with soil, which acts as an electrolyte.<\/p>\n<\/div> Galvanic corrosion progressively reduces the effective cross-section of buried conductors and weakens earth rods.<\/p>\n<\/div> A corroded electrode loses its ability to dissipate fault currents or lightning currents efficiently, potentially leading to non-compliance with standards.<\/p>\n<\/div> Localized corrosion can cause mechanical failure or disconnection, compromising the safety function of the earthing system.<\/p>\n<\/div> In short, any interface between dissimilar metals<\/strong> represents a potential galvanic risk.<\/p>\n<\/div> The following engineering best practices significantly reduce the risk of galvanic corrosion:<\/p>\n<\/div> Copper is widely preferred due to its excellent electrical conductivity and chemical stability.<\/p>\n<\/div> These solutions limit direct metal-to-metal contact between incompatible materials.<\/p>\n<\/div> Depending on soil resistivity, pH, moisture, and chemical composition, suitable options include:<\/p>\n In industrial or coastal areas, sacrificial anodes (zinc or magnesium) can be used to protect the primary earthing system.<\/p>\n<\/div> Galvanic corrosion is a natural electrochemical phenomenon, but its impact on earthing systems can be severe if ignored. By selecting compatible materials, protecting metal interfaces, and accounting for environmental conditions from the design stage, engineers can ensure long-lasting, reliable, and safe earthing installations<\/strong>.<\/p>\n We recommend the use of the following galvanic couples:<\/strong> <\/p> What Is a Galvanic Couple?<\/strong><\/span><\/h2><\/h2><\/div>
\nDue to their different electrochemical potentials, one metal becomes the anode<\/strong> and corrodes preferentially, while the other becomes the cathode<\/strong> and is protected.<\/p>\n\n
Why Are Galvanic Couples a Problem in Earthing Systems?<\/span><\/h3><\/h3><\/div>
Main consequences include:<\/strong><\/h4><\/h4><\/div>
1. Degradation of electrodes and conductors<\/strong><\/span><\/h5><\/h5><\/div>
2. Increase in earth resistance<\/strong><\/span><\/h5><\/h5><\/div>
3. Loss of electrical continuity<\/strong><\/span><\/h5><\/h5><\/div>
Where Do Galvanic Couples Occur in Practice?<\/strong><\/span><\/h2><\/h2><\/div>
\n
How to Prevent Galvanic Corrosion in Earthing Systems?<\/strong><\/span><\/h2><\/h2><\/div>
1. Use homogeneous materials whenever possible<\/strong><\/span><\/h3><\/h3><\/div>
2. Use bimetallic or insulating connectors<\/strong><\/span><\/h3><\/div>
3. Protect all junctions<\/strong><\/span><\/h3><\/div>
\n
4. Select earth electrodes according to soil conditions<\/strong><\/span><\/h3><\/div>
\n
5. Use sacrificial anodes in aggressive environments<\/strong><\/span><\/h3><\/div>
Designing for Durability<\/strong><\/span><\/h2><\/h2><\/div>
\n\u2022 Copper \/ Copper
\n\u2022 Copper \/ Tinned Copper
\n\u2022 Galvanized Steel \/ Galvanized Steel
\n\u2022 Stainless Steel \/ Stainless Steel<\/p>\n<\/div><\/div><\/div><\/div><\/div>Contact<\/span><\/h4><\/h4><\/div>\n
<\/ul><\/div>\n