The AHJ has no authority concerning the construction of a listed product. ...
Ahhh, were that they believed that too...
berzerk,
Did he cite a reason? Your thread title says "dissimilar conductors", is that what he said or is that speculation on your part? Because if that's his theory as to why it can't be done, then what about the bolts? What about the aluminum lugs that are frequently used to tap off of copper bus bars? If you had silver plated bus, then must you silver plate all of the tin plated circuit breaker and cable lugs that attach to it?
I'm not sure this is specifically regulated by code because it's really a non-issue. Bus bars are plated to avoid oxidation because copper oxide is a poor conductor. Once plated, the plating material is of little consequence (other than silver being bad for areas with sulfur in the atmosphere).
Dissimilar metals is a problem when you connect them in non-electrical applications (like plumbing) because it CREATES a current flow that then can lead to
galvanic corrosion. But for galvanic corrosion to occur, it needs the presence of an electrolyte (such as water), something that is EXPRESSLY excluded from electrical gear! So if he is insisting on a code citation allowing you to use dissimilar plating materials, he might as well ask for a code citation allowing you to enclose equipment in steel boxes that are not coated in insulating materials.
Your gear is UL listed. He can take it up with UL, they will tell him it's not part of their procedures. I used to work for a gear mfr, we had an inspector red tag a project because our horizontal bus arrangement was not A-B-C front-to-back, which
IS in the code if you were fabricating something in the field. But our gear was UL listed, so the code stopped at our enclosure walls. He insisted on a UL inspection, we eventually gave in and the UL inspector looked at it and said "So what? Not an issue" and left. We had to pay the UL bill ($2K!) but when there were change orders, we got it all back.
