I had to Tig weld(208V) a machine that has proprietary motherboards and electronics on board and is a 208V machine. I turned it off but left it plugged in with the thought that if the TIG welder current were to stray it would go into the earth ground connection. But today we are having an anomaly and I am hoping I didnt fry something.

What is the proper procedure when welding on a machine that has electronics on board?