You need to try isolating the HF as much as possible. It's noise can affect electronics everywhere. Ground the sub panel as you are planning, also drive another ground rod next to the welder and ground it. run a ground wire from the soil ground at the welder to your work table. I have a welder in my garage also plus a 3axis machining center. I was welding aluminum one day (HF continuous) while running a 3d machining operation and the hf cause my work coordinate to shift in my mill. It used to send my vcr into fast forward while playing a movie. I've seen it type in characters in a computer just by waving your hand over the keyboard. I have a miller 350LX Syncrowave machine and the manual gives a diagram of how to ground the hf.
Ken |