In GTAW, how does DCEN compare to DCEP in current-carrying capacity?

• A. DCEN ten times greater than DCEP
• B. DCEP ten times greater than DCEN
• C. They are equal
• D. DCEN has half the capacity of DCEP

Answer: (A)

In GTAW, the way polarity is set changes where most of the arc heat goes, which in turn affects how much current you can safely use. With straight polarity (electrode negative, workpiece positive), the arc heat is directed more into the workpiece, helping the weld to penetrate while keeping the tungsten electrode cooler. That cooler electrode can carry higher current without overheating, so the practical current limit is higher. With reverse polarity (electrode positive, workpiece negative), more heat concentrates at the tungsten tip, causing faster electrode wear and a lower practical current limit. Because of this heat distribution, straight polarity is described as having greater current-carrying capacity than reverse polarity, often summarized as a substantially higher capacity (a rule-of-thumb figure such as ten times greater is sometimes used). In short, DCEN allows higher current than DCEP due to cooler, less stressed electrode during GTAW.