Exothermically welded connections and mechanical connections are very similar in their applications, yet their performance can differ greatly.
As UK distributors of ERICO CADWELD welding systems, we explore the benefits of a exothermic bonded connection over mechanical connectors.
The CADWELD Weld
– Will carry more current than the conductor.
– Will not deteriorate with age.
– Is a molecular bond that eliminates any risk of loosening or corrosion.
– Will resist repeated faulty currents.
– Can be quality controlled simply by visual inspection.
As the molecular bond eliminates the concept of surface contact, an electrolyte cannot penetrate between the conductors and cause oxidation and deterioration in the course of time.
This reliability is of particular interest for humid or chemical environments or for bonds directly buried in the ground.
Ability To Withstand High Current
The melting temperature of CADWELD filler material is higher than the melting temperature of copper (1082oC). For this reason, in the event of abnormal heating due to a high fault current, the conductor is destroyed before the connection.
The CADWELD connections form a solid bond around the conductors assuring continuity. The cross sectional area of the weld has greater current carrying capacity than the conductors.
Standard CADWELD welds have a cross section greater than that of the conductors to be joined, which compensates for the difference in resistivity between the conductor and the welding material. Consequently, under fault conditions, the weld will always remain cooler than the conductor.
If special applications do not allow for the required increase in cross section to be employed, the use of the formula:
Which will make it possible to define precisely the resistance of the CADWELD weld.
Comparison between CADWELD bonded connections and mechanical connections
|CADWELD Weld||Mechanical Crimped Connection|
Actual Contact Surface
|The CADWELD bonded connection provides permanent conductivity over the whole of the section due to a molecular bonding between the metal surfaces.||The mechanical connection presents a significant difference between the apparent contact surface and the actual surface.|
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