Surface treatment of overhead power cables involves a lot more than just cleaning. It has a direct influence on thermal performance, corrosion resistance and service life.
Two common approaches are acid pickling and wet blasting. Both remove oxides and deposits, but the results are very different.
Why wet blasting is the better option:
✅ Higher emissivity
• Wet blasting creates a textured, matte aluminium surface.
• Typical emisivity values: 0.6 to 0.8 for wet blasted surfaces compared with 0.2 to 0.3 for pickled surfaces.
• The increase in emissivity improves heat dissipation, lowering operating temperature and reducing conductor sag.
✅ Improved corrosion behaviour
• Blasted surfaces support the growth of a uniform oxide layer with good protective properties.
• Pickled surfaces can remain chemically active and more susceptible to localised attack if residues are present.
✅ No chemical residues
• Wet blasting relies only on water and abrasives, avoiding the risk of trapped acids or salts.
✅ Consistent and controllable finish
• Surface roughness and texture can be adjusted by changing abrasive type, hardness and pressure, ensuring predictable results.
✅ Environmental and safety benefits
• No acid handling, fume extraction or neutralisation of effluent is required.
In practice:
Raising emissivity from about 0.25 to 0.7 can reduce conductor surface temperatures by 10 to 20 °C under load. This extends service life and enables higher ampacity.
For transmission operators and asset managers, wet blasting offers a route to safer conductors, higher thermal margins and longer service intervals - while also reducing environmental impact.
