Electrician's Licensing Practice Exam

What process involves the fusion of metal materials or copper to rebar?

1. Arc welding

2. Exothermic welding

3. TIG welding

4. MIG welding

The correct answer is: Exothermic welding

Exothermic welding, also known as thermite welding, is the process that involves the fusion of metal materials, specifically using a chemical reaction to create extreme heat that melts the metals. This method is particularly effective for joining copper to rebar because it does not require any external power source and can produce a strong, conductive bond that is resistant to corrosion. The process starts with a mixture of metal oxides and aluminum powder. When ignited, this mixture undergoes an exothermic reaction which generates molten metal. In the case of copper and rebar, the molten copper is poured into a mold that holds the rebar, creating a solid and durable joint once it cools. Understanding this method is crucial for applications in electrical grounding systems and structural connections, where a reliable and conductive joint is necessary. In contrast, other methods like arc welding, TIG welding, and MIG welding typically rely on an external power source and may not be as effective for this specific type of metal fusion due to the characteristics of the materials involved.