What Is Exothermic Welding And Why Is It Used?

Exothermic welding – also known as thermite welding or exothermic bonding – is a process for permanently joining earthing (grounding) or lightning protection conductors together.

An exothermic weld can be especially useful for joining dissimilar metals. The process has the advantage in that it requires no external heat source and works by employing a chemical exothermic reaction of a thermite composition (weld powder) to heat the conductors to a point where a low resistance, mechanically sound molecular bond is formed once cooled.

Exothermically Bonded Connections

Although mechanical connections and exothermically welded connections are very similar in their applications, their performance can differ greatly.

Our “Traditional” and “PLUS” exothermic welding material is suitable for welding these materials together:

  • Copper
  • Mild steel
  • Bronze
  • Brass

Specialised applications would also include cast iron and stainless steel materials, please speak to our Sales Team: 020 8405 6789 or email: sales@etscablecomponents.com.

Exothermic welding is the only reliable means of bonding galvanised mild steel to copper conductors, e.g. fence earthing or structural steel applications. ETS is the authorised UK re-seller and stockist for nVent ERICO Cadweld® exothermic welding products


  • Will not deteriorate with age.
  • Eliminates any risk of loosening or corrosion due to its molecular bonding characteristics.
  • Will resist repeated faulty currents.
  • Offers the lowest possible earth path resistance.
  • By visual inspection can be quality controlled.

Exothermic Welding Training

ETS can provide in-house training at short notice (UK only), either at our training facility or at a customer’s site for the nVent ERICO Cadweld® exothermic welding system.

These courses are designed to show and teach the correct preparation procedures, use and applications of the CADWELD® welding system. You can find out more about our exothermic welding training courses here.

Watch this video on exothermic welding:

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