Which polarity yields the deepest penetration in SMAW?

• A. Direct current electrode positive [DCEP]
• B. Alternating current (AC)
• C. Direct current electrode negative [DCEN]
• D. Direct current with reverse polarity

Answer: (A)

Heat placement in SMAW is what drives penetration. When the electrode is positive (DCEP), the arc delivers more heat into the workpiece, causing the base metal to melt deeper and the weld pool to penetrate further. If the electrode is negative (DCEN), more heat goes into the electrode itself, resulting in shallower penetration. AC switches polarity, so the heat distribution alternates and the penetration is less consistent and typically not as deep as with DCEP. Therefore, the setup with the electrode positive yields the deepest penetration in SMAW.