The life of an earthing network is determined not by the conductors but by the connections. In a system buried underground the conductor can go on doing its job for decades; but a single connection that has loosened or corroded ends the electrical continuity of the whole network. What is more, this fault is invisible to the eye — it can only be found by measurement, and often only once it is already too late.
Exothermic welding (thermite welding) joins two conductors with molten copper, making them a single piece at molecular level. The resulting connection has the same current-carrying capacity as the conductor itself and is sealed against corrosion underground. This is why it is our preferred method for permanent earthing connections.
At Yılkomer we supply exothermic welding system equipment and carry out the application with our specialist team.
Four Defining Advantages of an Exothermic Weld
The high temperature released during the reaction melts the conductor surfaces and produces a true metallurgical bond. The resulting connection is not a mechanical contact but a single, continuous conductor.
The connection point behaves as though it had the same cross-section and the same conductivity as the conductor itself. Under impulses as high and as brief as a lightning current, no heating or constriction occurs at the connection point.
In mechanical clamps the gap left between the two metal surfaces is open to moisture and to the soil; over time it oxidises and the resistance rises. In an exothermic weld there is no such interface; the connection keeps the performance it had on the day it was buried.
It calls for no torque checks, no re-tightening and no clamp replacement. This is the internationally accepted approach for permanent connections; standards such as IEEE 837 define permanent connection performance in these terms.
Equipment and Consumables
- Exothermic welding moulds — Graphite moulds specific to the conductor type, its cross-section and the connection geometry (T, X, straight splice, connection to a rod, and so on).
- Mould holding clamp — For securing the mould safely and in the correct position.
- Ignition system — Equipment for safe remote ignition.
- Ignition system — Remote safe ignition equipment.
- Mould cleaning and maintenance kit — Brush, scraper and the ancillary equipment that extends mould life.
- Conductor preparation tools — Tools for cutting, straightening and surface cleaning.
- Personal protective equipment — Gloves, face shield and heat-resistant equipment.
The Application Process
- Determining the connection type. A mould suited to the conductor cross-sections and to the geometry is selected.
- Surface preparation. The conductor ends are cleaned and brought to a dry, oxide-free condition.
- Setting up the mould. The mould is heated to drive off moisture and the conductors are fixed in the correct position.
- Placing the tablet and ignition. The dosed tablet is put in place and ignited from a safe distance.
- Cooling and inspection. After the connection has cooled, a visual check is carried out and, where necessary, a continuity measurement.
- Recording. Every connection point is marked on the project drawing and reported.
