The welding transformer can produce high currents. Current from the welding transformer passes through a cable and then through the electrode into the work piece which is earthed or connected directly to the transformer.
An arc is generated by touching the work piece with the electrode and then breaking the contact. The high current which is interrupted now forms an arc as it tries to jump across the gap between the electrode and the work piece.
Shielded metal arc welding is widely used in almost all industries. It is also used in construction. Shielded metal arc welding can be used to weld both ferrous and non-ferrous metals.