I am redoing a ceiling fan with new wiring. I have the walls open at the switch box. There is an old knob & tube hot wire coming in and then it goes out to the ceiling fan. I have run new wiring to the ceiling fan and have put an outlet right below where the new plastic box is going for the switch. I can't find where the feed is for the hot wire, it is somewhere in the ceiling. I have gone to the other fixtures that are on the same breaker and don't see the hot wire being fed from there. What do I do with this?

  • Are you asking if it's OK to leave the K&T wire in the ceiling box and just not use it (which would be the easiest) or are you hoping to remove all unused K&T wire, but not sure where it originates? Sometimes K&T is spliced inside walls and ceilings w/o a box. – Rand May 9 '14 at 18:42
  • It is hot at the switch and that is where I would have to leave it. There are only two wires that come into the switch box, the hot coming in and then it goes out to the light. If I disconnect the wires at the switch, the wire going to the light is going to be dead but the other wire is going still be hot. I am planning on getting my new feed from the outlet box directly below the new switch box. – john May 9 '14 at 19:05
  • If that's as far as you want to tear into things, there's nothing wrong with wirenutting or taping it and leaving it in the box. The worst thing about K&T is its age and only you know the condition of its insulation. Tape it all up if you have to and don't bend it around too much. – Rand May 9 '14 at 19:29
  • It hit me right after I clicked add comment. You want to get rid of the old sw box right? You said your wall is open so you're looking right at it along side of the stud? Remove the old box and cut the hot wire or both of them within a few inches of a knob or tube and tape or wirenut it. If you can't see a knob or tube, beef up the insulation with tape or heat shrink tubing for a few inches and gently staple it to the center of the stud. – Rand May 9 '14 at 20:00

You must terminate the wire in a box and it must remain accessible with a cover plate. You need to terminate it with the appropriately sized wire nut.

This may help locate the hidden splice: get a voltage sensor ($5), turn off all breakers except for this one. Put the sensor on high sensitivity and start sweeping around on the ceiling. You might get lucky and find a hidden box or at least you'll get to know how the wires are run and get a better feel for which switch or light box contains the feed.

  • Perhaps a new "knob" is needed so that the wire is properly tensioned? – Pigrew May 9 '14 at 18:19
  • I am not sure that a new knob would do anything, the issue is what to do with the old hot wire for the switch/ceiling fan that is being replaced, not anything to do with tension. – john May 9 '14 at 19:10

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