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How do I reconnect my old knob-and-tube wiring to a new box. My issue is my furnace will not come back on until the knob-and-tube wiring is connected to the new main breaker box. This is a temporary fix to a costly repair I cannot make until spring. But, I need heat now for the winter. So how do I reconnect the wires?

Daniel Griscom
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Sherlivia Lynne Thomas-Murchis
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    Can you provide a picture of your panel and wire?? – JACK Nov 17 '19 at 01:19
  • Hello, and welcome to Home Improvement. We'll need more info before we can help you. And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Nov 17 '19 at 01:29
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    The knob-and-tube wiring is unsafe. You really don't want to take the risk of re-connecting it. Run proper wiring to your furnace. – jwh20 Nov 17 '19 at 01:36
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    There may be a better way to get through the winter than re-energizing obsolescent wiring. How is the furnace connected to the K&T wiring? Does the wiring run to an outlet, with the furnace plugged in? Or does the wiring run directly to the furnace? – A. I. Breveleri Nov 17 '19 at 03:14
  • How far is the furnace from the breaker box, and are there walls/... in the way? Also, can you provide photos of the situation? – ThreePhaseEel Nov 17 '19 at 03:43
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    @jwh20 -- K&T is not categorically unsafe...the main issues with it are simply "old wire/wiring issues" – ThreePhaseEel Nov 17 '19 at 03:44
  • @ThreePhaseEel I have yet to see "safe" K&T wiring. I've never seen an installation that didn't have crumbling insulation, loose or broken knobs and tubes, improper splices, or exposed conductors. In my opinion, it's unsafe all the time. – jwh20 Nov 17 '19 at 11:39
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    @jwh20: K&T is not categorically unsafe. Where I live, the Greater Boston area, all the up to 120 year old K&T that has not been messed with is in excellent shape. It is only hazardous where it has been carelessly connected to new wiring or new fixtures without the proper junction boxes and insulated bushings. – A. I. Breveleri Nov 17 '19 at 18:58
  • But HOW DO YOU KNOW if it's been messed with or is otherwise compromised without opening up all the walls and inspecting it? At that point, it's best to just replace it. – jwh20 Nov 17 '19 at 23:11

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I agree with 3phase , the wiring in many old homes is still k&t , the junctions still require to be in a box , I was trained to use western union splices 7 turns minimum for both T taps and splices after wrapping they were soldered and this is still ok today , code states you can not use solder only the wrapping is the mechanical part. Since you are going from K&T to probably romex you may not have a box so you need a new box with insulated bushings for the wires to enter you will need a pair of knobs outside the box to anchor the wires through the insulators and into the box. I use shrink tubing But fiber insulation can be used then wire nut from the old to new and install the cover. This method will pass inspection as long as your AHJ allows , I did quite a few Over the years I only mentioned the turns because to meet historical accuracy that was required , wire nuts are better today since you are converting the panel.

Ed Beal
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  • I ran into a lot of K&T in New Orleans after Hurricane Katrina. Moldy drywall was removed so we couldn't cover the K&T back up. A lot of it seemed better than what we were replacing it with. – JACK Nov 17 '19 at 15:23