I am doing a minor reno in a new house. I took out a wall and in it was two strands of 12-2 that went to one outlet. That wiring will not be used anymore, I don't want to splice into them or run them to a different location. I can not tell how the wires run back to the box so I can't pull them out so I want to hide then in the floor. Can I just cap it with some wire screws? Or should I put a box around it? The box is less favorable because I would have to cut a hole in the sub floor to hide it. But is that the safer option? Thanks J

  • 2
    A wire tracer can help you follow the wires back to their origin. If they still have power, one that f the circuit-breaker identifying transmitter/receiver pairs can sometimes be used as a poor man's tracer. If you can't do that... Is this someplace where a floor outlet might make sense? – keshlam May 3 '16 at 16:57

Junctions and terminations must be in a box, and the box must be accessible. You can't bury it under a floor. Unless you have an idea where the source is, you'll need to treat the wires as though they're live.

  • Thanks! Should I splice into the wires then and run them to a dead end in a wall and in a box? And if I do that can I connect the 2 in wires to one out? – joby dorr May 3 '16 at 16:57
  • What would be the point of that? You can't splice without a box, and then you have a box. Why add more wire and a second box for an unused circuit? – isherwood May 3 '16 at 16:57
  • So should I just put a box in the floor with an access plate? Kind of a bummer to have a plate in the floor – joby dorr May 3 '16 at 17:00
  • 1
    That's what's required by code. Whether you do things in some other safe way is your call. – isherwood May 3 '16 at 17:03
  • 1
    What's under the floor? A basement? Put the junction box in the ceiling of the basement. – longneck May 3 '16 at 17:12

There are splices rated for being closed up behind a wall without a junction box.


  • 1
    Those splice kits are only acceptable in limited situations. – Tester101 May 3 '16 at 17:19
  • +1 The code does allow this type of splice. But as Tester101 says, the circumstances are limited and it is generally considered a last resort solution. If you expand your answer to give the code cite and the circumstances of use, this would be a helpful answer. – bib May 3 '16 at 17:24
  • Due to a slight change in the 2014 NEC, these devices may actually be allowed in this situation. 334.40(B) Devices of Insulating Materials. Self-contained switches, self-contained receptacles and nonmetallic-sheathed cable interconnector devices of insulating material that are listed shall be permitted to be used without boxes in exposed cable wiring and for repair wiring in existing buildings where the cable is concealed..... See this answer for the older wording. – Tester101 May 3 '16 at 17:34
  • However, I'm still not sure this situation fits, as this isn't technically a "repair". – Tester101 May 3 '16 at 17:36
  • @Tester101 I think we need a write up on the current code and the use of these splices, both the rules and best practices. – bib May 3 '16 at 19:04

Once you trace the wires (I would use first a voltmeter to figure out which breaker shuts it off) then you will want to disconnect the other end, even if it is coming from another outlet.

Sometimes (when the breaker is off) I have used a toner/tracer to follow a wire.

The code is not concerned about totally disconnected wires. They are about as interesting to the NEC as the nails that hold the wood together.

Then I would cap both ends with wire nuts just to complete the job. Maybe even wrap each end (with the nuts) with electrical tape to show it is inactive.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.