How can I rectify a safety concern involving exposed individual wires?

Question

I was adding lights in a basement closet and when I cut the ceiling open this is what I found.

It looks like previous owners didn’t bother protecting wires or moving boxes outside of the drywall when they did a remodel in 2000. I can lower the box down so it can be accessed once the drywall goes back up.

Obviously it Isn’t practical to tear out an entire finished basement ceiling to properly rewire and pipe the THNN. What would you do to make this situation safe that is practical?

Update: I opened up the entire ceiling in the closet and sure enough the vertical drops are right there for the outlet and light switches above. Would it be possible to use an adapter to connect conduit to those vertical runs? I would use a new box obviously and would have access to that in the ceiling with a blank face plate. It is a closet so that plate won’t bother me. Would this be acceptable solution?

Answer 1

By "feel safe" I think you probably meant "be safe." And I can't see how to make the installation safe other than putting in code-compliant wiring. How big of a job that is depends on some things you didn't mention, such as the size of the basement, length of wire runs, etc.

The photo you posted shows a junction box that was hidden, without a cover, without strain relief, and with a mess of electrical tape of unknown purpose. So it isn't just that THHN wire was run outside of conduit; there appear to be a multitude of safety issues. I wouldn't "feel safe" until I had followed any suspect runs of wiring and discovered any and all deficiencies.

Since the THHN was not run in a code-compliant way, I doubt it is stapled or otherwise secured inside the wall. This may allow you to use the THHN to pull new NM cable instead, which does not require conduit. Doing this may allow you to open less drywall.

I feel for your situation. I am not a professional and home renovations can be very stressful. I wish you the best!

Answer 2

A few years ago I moved into a house and discovered that one area of suspect wiring actually was a lot of wiring not up to code throughout the house. Not just knob and tube, also lack of ground wires and mismatching wire gage to breakers. This answer isn't about specifics to fix, more general based on my experience and the help of a great electrician:

1. The help of a great electrician is invaluable. If cost makes this impractical, you need to prioritize what can be done as I said in part 4. I was lucky to find an electrician who was willing to get hands-on with the tricky things and was willing to inspect my DIY work on the easier labor (they knew that I had familiarity with electrical and am a careful person).

2. You can rapidly make this safer by putting extra protection on the circuits, such as AFCI and GFCI breakers, as Ecnerwal said. We did this in my case and the more I learned about electricity, the better a move it seemed.

3. Come up with the simplest method to make your use case safe, starting from what you have now. Often times we found that redoing shoddy work was a lot more work than just removing/disabling shoddy work and creating a safe setup from scratch. A good electrician can help problem solve here as they will be more familiar with what works and doesn't for routing wires, meeting different use cases, making shoddy work safe etc. For example, like stmp945 said, maybe you can tape NM wiring to one end of the THHN and pull the THHN through to get the circuit rewired without much trouble. Alternatively, you could see if there are safe parts of that or another circuit which you can safely extend to power this light you want.

4. Inspect your panel to see if anything needs to be made safe there. From then on, prioritize circuits that are known to have problems (like what you found) and circuits that are more likely to create hazardous situations (like those servicing wet areas, outlets for electrical heating,or other high power use). I say that because there is only so much you can do at once (and again, by prioritizing AFCI+GFCI protection, you can at least reduce fire hazard fairly quickly).