Thank you, Jim, for your response. After some research, I've decided to replace the entire circuit, from panel to outlet. Watching some of the videos linked to yours, there is much preparation to do with the connector itself, as well as the products to purchase for protecting the splice. And still, it was pointed out, this application may have problems in the future. So, to eliminate the possibility of failure or worse, I believe the safest way is to make the necessary openings in the floor or ceiling, and run an entirely new circuit. Once again, thank you for helping me.