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Should I Keep Knob-and-Tube Wiring?

  • Transcript

    LESLIE: A.J. in Iowa is on the line with an electrical issue. Tell us what’s going on.

    A.J.: Well, I bought a house recently. Moved in April 1st. And when we had the inspection done, the inspector said up in the attic, there was some knob-and-tube wiring.

    TOM: Right.

    A.J.: And he said I should probably get it replaced. I did some of my own research and I was a contractor back in – a subcontractor in college, so I kind of want to do all the work myself.

    TOM: OK.

    A.J.: But I’m kind of wondering if that’s something I should really try to tackle, because my research says that some of it says you can keep it if it’s OK or …

    LESLIE: Knob-and-tube?

    A.J.: Yeah.

    LESLIE: I don’t know if I would keep any of it in function.

    TOM: No. I would definitely not keep knob-and-tube. Let me tell you why. Knob-and-tube wiring is ungrounded and ungroundable.

    A.J.: OK.

    TOM: So that’s why it’s not a good thing to have. And do you know why it’s called knob-and-tube and what the purpose is of the knobs and tubes?

    A.J.: Well, I’ve just – looking at the pictures, I see the little ceramic knobs, I guess, that counteracts the live wires around it.

    TOM: Right. But let me explain to you – let me tell you what’s the reason for that. The reason for knob-and-tube – the structural reason for it – where you have these ceramic knobs that hold the wire away from the beam, that’s because the wires have to air-cool. You need to have air around them because they overheat. And the tubes just protect the beams from catching on fire as the knob runs through it. So these are wires that are designed to run hot. In fact, you cannot even put insulation on top of it.

    So, we would recommend that you deactivate all the knob-and-tube wiring and replace it with modern wiring. It’s just not safe at this point. It’s near 100 years old and I just wouldn’t take a chance.

    A.J.: Oh, is that something that I could probably tackle myself then? I mean I don’t have an extensive electrical background but I …

    TOM: Well, I think that you could probably – if you know how to turn the circuits off, you certainly could rip out the old wiring. But rewiring your entire house? No, I think you need a little more experience for that, A.J.

    A.J.: OK. Well, I appreciate it.

    TOM: You’re welcome. Good luck. Thanks so much for calling us and I’m glad we helped you out.

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