The study presents results of research on the application and usability of variable polarity MAG welding of thin protective-coated sheets in automotive industry. The research-related process was carried out using OTC Daihen DW 300 and Cloos Qineo Champ welding devices. The study also discusses the influence of EN ratio in the course of current and voltage on the stability of process, quality of joints, and the degree of damage to protective coating.