Green wire in a EMT conduit run
Old house with all rigid conduits and metal boxes. While trying to figure out what is what I noticed a green wire coming out of a conduit into a box and attached to the green screw on the box.
I checked where this green wire comes from and it runs all the way 75 feet back to the panel and attached to the neutral bar where all the white wires are.
One long conduit run, nothing in between. Double checked.
Why would someone run a green wire all this way when there is continuity from there all the way back to the panel box?
Now get this, inside this metal box are two circuits sharing one neutral white wire.
While this is not uncommon, I got the feeling the green wire was meant to be a neutral wire originally, perhaps due to someone running out of white wires but have green ones around...but neglected to label it as such. So they ran a green wire as a neutral. Later on, someone opened the box in isolation and saw that, and decided it was incorrectly wired, and created the shared neutral circuits, and attached the green wire to the box.
Does this make sense? Can you think of a reason to run a 75 foot home run green wire in an install that's all EMT and metal boxes?