I have a 1950's bungalow which originally had ungrounded outlets. Before we bought the house, someone decided to install 3-pronged outlets by fishing 14 AWG THHX green wire up through the exposed basement ceiling to each outlet. They are not daisy chained outlet to outlet, each outlet has a single green wire running to it and pushed up into the box. At the other end, they randomly spliced all these green wires together, outside of j-boxes, with simple electrical tape before running them to a 6 AWG bare copper wire attached to the copper cold water inlet. There's only a main panel (no subs) and it is grounded by a rod running into the cement floor under the panel (not to the cold water inlet).
I've read elsewhere on this forum that running retrofit grounds is OK. My question is on the mechanics.
If it's retrofit, is it OK to have THHX wire running without conduit? Would running bare copper be better / require a conduit?
What should really be done with all the ends? Can they all be spliced together into an accessible j-box near the panel and then be clamped onto the main ground through a single wire instead of to the copper water pipe?
For those who are going to suggest GCFI, the boxes are old school small things with 2 big nails driven through the middle of them. I don't think there's room without tearing out the old boxes to just pop a GCFI in there. And I'd kinda like to have equipment grounding if possible.
As for running new NW between the outlets in the currently exposed basement ceiling, there's a potential problem in that the outlets are on the same circuit as the ceiling lights in the individual rooms. I haven't figured out the exact sequence in each room. I don't care if the ceiling lights remain ungrounded, I just don't want to take the outlet out of the circuit and put it on a new circuit run through the basement and find out I've interrupted power to the ceiling light. Also, what would I do if I can't get the old (potentially stapled wire) between outlets out of there, do I just leave it in the wall?
Thank you so much for any help.