What may occur if you touch the metal table with unprotected skin during GTAW?

• A. An uncomfortable shock due to high frequency start
• B. A mild tingling sensation
• C. A loud bang
• D. No hazard

Answer: (A)

High-frequency start in GTAW can couple energy to grounded surfaces, so touching a grounded metal table with bare skin can produce an uncomfortable electric shock. The TIG welder uses a high-frequency oscillator to ionize the arc and initiate the weld. Although the main welding current flows between the electrode and workpiece, leakage and capacitive coupling can put HF energy onto nearby grounded conductors. When your skin provides a path to ground through the table, a small current can flow through you, giving a noticeable jolt or tingling sensation. To minimize this risk, keep skin insulated from grounded surfaces, wear dry insulating gloves, stand on an insulating surface, and ensure the HF circuit is properly managed and the workspace is dry.