Panel box ground ?????

Has anyone ever seen this in a 200 amp panel box. The grounding wire goes from the buss bar to the grey knob on the side of the panel box and no where else. There is no grounding wire or grounding rod except for the grey colored knob on the side of the box

That grey box looks like a surge protector or lightning arrestor.

Never seen that before. Is it possible that the GEC goes into the wall and the gray thing is covering it? It there a GEC termination on the water pipe?

Grey knob is only on the box, I slipped a piece of paper behind it to make sure it wasn’t attached to anything

How many wires are coming out of it, just one?

Nothing comes out of the knob, only the ground wire goes into it

There should be three conductors. Are you sure there is only one?

looks like a lightning arrester to me as well. Check it again because it looks like more than one conductor is coming out of it…but then again I am not at it to see it…just my thoughts.