I have replaced all old outlets with existing wiring (no ground) on 20 amp circuits in 1950 home with new tamper resistant 20 amp decora outlets.
Before doing this I had an electrician trace for placement of GFCI outlets so they are at the front of each run. The boxes are all metal and different from any I have seen (picture attached).
I am wondering if the metal bar in base is some sort of ground or brace?
Additionally, the electrician told me that I should add a copper ground wire from the receptacle ground to the box, so I did. I added the wire to all receptacles including the GFCIs.
All boxes still test as if they have no ground with a plug in tester. All labeled GFCI protected and No Equipment Ground. I just read somewhere that adding the copper wire could electrify the box and then I have read here something that said it is pointless to do but it won't cause any issues.
Can I leave the copper wire connected to all these boxes or do I have to go back and take it out? Is there anything special about these boxes?