Mine is only one experience but I work an a building apprx. 200,000 sq. ft. and 40 feet tall. Lots of steel structure. All our maintenance welding is done by rolling the welder to the nearest 3phase 480v outlet, plugging it in, and hooking the work clamp to the beam the outlet is mounted on. In over twenty years, I have not heard one report of any problems caused by this setup. I tend to favor EVERYTHING bonded together
