Hi all.
So a few weeks ago I got a 2021 350G. I'll get that in a signature later.

Yesterday I was working on installing my E-Track in the garage. I'm using nuts and bolts. So at first I was sitting on the rear stairs, putting the nuts on the underside. I felt a few times like I got stabbed or bit in my arm that was resting on the top stair, but there was some dirt and drill shavings there, so I didn't think about it too much.

I moved to the next section, which was laying on the ground to the rear of the stairs. As I reached up my arm touched the metal skirt panel that comes down below the frame. More stabbing. I finally figured out at this point I was getting electrocuted. (very mild, I'm fine)

I unplugged the shore power, and no more shock. I take this to mean it's not a 12v source, and must have a short to the frame somewhere in the 120 system. I did a couple tests to see if I could find it, but didn't really point me anywhere. The first test was checking continuity between each breaker and chassis ground. No tone. I didn't check actual resistance because I wasn't sure what range to try. The next test I did was to stick my ground probe into the dirt, and check for AC voltage. Sure enough, about 16v off the stairs and that skirt. I didn't check any other locations. The next test, I flipped each breaker one at a time, with the mains being the last. Each one brought the 16v down a volt or 2, but no single one cut it entirely. I think we still had 8v with the main breaker off.

I'm not really sure where to go from here. I feel like it could be something before the breaker box, but if that's the case why did it step down with each one turned off? I know I could have an issue anywhere, but is there anywhere more likely than another place?

Thanks,
Brian