Method of aluminothermic welds qualification for down conductors and earth-terminations systems

The IEC 62305-3 imposes the use of copper cables of at least 50 mm² for down conductors used in lightning protection. The cross section is an important factor to carry lightning currents in LPS. However, it is possible to connect these conductors in various ways. Among the different methods used in meshed network, aluminothermic welds are relevant. This process has the advantage to be corrosion proof to have good electric characteristics compared to others methods, with good mechanic holding performances. Sometimes, this method modifies the conductivity of the conductors. This is the reason for which we perfect a method to verify whether the weld changed the material or not.