What are the safe and compliant options for terminating an unused knob and tube branch? In this instance, insulation will be applied, so the fixtures and receptacles previously on this circuit have been wired to a completely separate circuit of Romex. This is on a third floor, far away from the panel.

I had an electrician complete this work, but I’m not very confident in the mess of wires he left in the attic. What type of termination should I be looking for in order to feel comfortable proceeding with insulation?

Wires in cavity between roof and 3rd floor ceiling: Wires in cavity between roof and 3rd floor ceiling A wire nut can be seen in the open air

  • How about some pictures so we can see what you see.
    – JACK
    Sep 14 '20 at 1:53
  • @JACK I added an image. A wire nut can be seen on one of the connections. I didn’t test all of them, but I believe (and hope) all of the wires without nuts are not live
    – Ivan G.
    Sep 14 '20 at 2:26
  • It's hard to tell what's going on there but it looks a little scary. When I have had to rework a portion of K&T, I have always removed as much as possible the cable/wire I was eliminating and did all splicing from K&T to NM cable in junction boxes that would remain accessible.
    – JACK
    Sep 14 '20 at 2:54
  • Is putting a junction box in there an option? Sep 14 '20 at 3:13
  • @ThreePhaseEel I don’t see why not. I think perhaps the only reason he didn’t is because it was near the end of the day when I reminded him insulation will be installed. I said I wanted all of the K&T disconnected, so he removed an existing connection (to an unused branch) shortly before leaving. All of this kind of points to a rushed job to me, he was just planning on leaving an unnecessary connection in place before I asked. And even further, I hope I can just terminate this in the basement instead of running to the attic on 100+ year old wire for no reason
    – Ivan G.
    Sep 14 '20 at 3:22

I'd have to go double check my NEC before saying for certain, but my recollection is that unless specifically tagged for future use old wiring no longer in service is supposed to be entirely removed. Now, there is some question of the practicality of that when the wiring is not in conduit, etc. but I would suggest getting as much removed as practical before insulating. Getting rid of all of it would be best practice. You also want to be very sure that if any of it is still hooked up anywhere it does not get buried in insulation.

  • While that's true for some things (comms wiring, most notably), there's no generic Chapter 3 requirement for removing unused wiring. It's definitely a good idea to not leave it lurking around, though, especially if it's obsolete the way the OP's is. Sep 17 '20 at 23:41

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