Final answer:
Arc blow is predominantly encountered when welding with DC power sources, as the consistent electron flow in DC exacerbates the phenomenon compared to the reversing electron flow in AC.
Step-by-step explanation:
Arc blow is a phenomenon encountered primarily when welding with a DC (Direct Current) power source. Although arc blow can occur with any welding power source, it is more prevalent with DC due to the steady flow of electrons that don't reverse direction as in AC (Alternating Current). Large circuit breakers and safety systems may use high-frequency AC or other techniques to mitigate this problem, such as insulating gas or jets of gas to extinguish arcs formed when high-voltage electricity is interrupted. Welders must contend with the challenges of arc blow as it can cause weld defects by deflecting the arc from its intended path during the welding process.