Make sure you’re buying 14/2 or 12/2 that has a ground wire and running that back to the breaker box. I saw the job you did with the big cable in the floor and it didn’t look like you ran a new cable that had a ground wire. It’s best to replace the old shoddy stuff with circuits that are up to code, even if you’re doing it DIY and your area doesn’t require homeowners to get it inspected. The codes are designed to prevent fires and loss of life.