Inspected this 1960’s home today and thought that the home had been rewired with grounded circuits. The 3-prong receptacles tested OK (grounded) with my 3 lite tester. When I opened the distribution panel, I did not see any grounding conductors, all 2 wire. Removed a receptacle and here is what I found. My question is would a sure-test indicate this false ground? What would this set up do to a appliance with a ground (3-prong plug) if current traveled back and energized the appliance. Looks to me like a real safety hazard. What do you guy/gals think?