Well executed joints with clamps and fasteners accomplish with the requirements of a good connection. That is, they are able to withstand and drive efficiently lightning discharges to the ground.
However, sometimes even with the best efforts of the installers, the suitability of these unions is difficult to determine, at least visually. First, screwed joints depend highly on the skill or even the patience of the worker for applying the torque to each of the bolts that the connector may have. It is, a priori, a simple task but often monotonous and repetitive especially for large installations, and therefore very susceptible to human error. Even worse, any failure is difficult to detect until the resistance of the whole installation is measured. Besides, maintenance is essential. Impurities, sparks or corrosion can lower the quality of the connections along time even if they are correctly made.
A solution for this problem is to change the mechanical connection for an exothermic welding with APLIWELD®, with better guarantees even along the time both for execution and verification of the connection.
The main difference is that, unlike joints with clamps, the welding is an irreversible molecular bond, a chemical transformation that cannot be reversed, where strengths along the conductors are uniform. The added material is copper thus having its electrical properties.
About the electrical properties of the clamps, it should be considered that: 1. there is always a gap between the connected conductors (there is "no chemistry" between them) and 2. the purity of the connectors can be highly variable, with a negative effect on the connection.
In summary, we can say that exothermic welding connections, compared with mechanical connections, have the same or better conductivity, do not increase the resistance, do not corrode or rust, they are more resistant to breakage and mechanical pressure because the formed material maintains its electrical and mechanical properties constant longer and these values are the same or even better than the conductors themselves.
As additional guarantee, Apliweld® exothermic (also called aluminothermic) welding, the system developed by Aplicaciones Tecnológicas, S.A. has passed the requirements UL467, a standard that applies to the quality of these type of connections, thus obtaining the UL Certificate.