First off,
Is there such a thing as a NON-CRITICAL welded component? "The Butterfly Effect" always comes to my mind.
I know, it is only a cable tray that carries all the Electrical power and Control Circuitry, Safety Systems, Alarms, etc.
I've never seen any welding performed on cable trays (was it really supposed to be welded in the first place?), they've all been mechanical connections and attacments. A S/S cable tray obviously is subjected to some serious corrosives or it would be just a galvanized tray. If this is merely a Farm Code (S/S trays, not likely!!!) job and all you're wanting to do is cover yours and your welder's behind, then, $5.99 at Walmart will get a rattle can of "Chrome" paint and all is good.
Of course, the only proper fix is to coordinate with the Electrical department, remove and replace the defective areas. Do it right...Period.
I have been involved with welding in close proximity to energized cable trays. With thorough protection from fire blankets and sheet metal (pipe insulation tin) it can be done safely.
I'd start off by having the Foreman or whoever is responsible for the welder join you in the Assesment and Corrective Action meeting. It's gonna be an interesting one for sure!
Best of luck to you, I feel your pain.