Talk:Knob-and-tube wiring

Increasing difficulty obtaining new HOI policies for K&T
John,

I am buying a home in NJ and it has 50% knob and tube wiring. It took me 3 weeks to find an insurance company to insure the wiring. The cost is $1800 for 6 months of coverage. The cost for replacing is 8,500. I close in December and it will be replaced in January-February. My policy will go down to $600 for a year. I agree with the others, coverage is impossible or unaffordable.


 * As my edit summary said a few weeks ago, availability of new HOI policies for homes with K&T that are being bought and sold is only sliding downhill. When I was calling around trying to find someone to write a policy, one guy hinted that I was basically ahead of the curve and that this was going to become a bigger problem in coming years. This will get solved on a case-by-case basis, as evidenced by your solution described above, but I think it is going to cause big headaches with surprises right before closing for a lot of people who thought everything was all lined up on their approaching settlement and then bam, K&T → no HOI → no mortgage approval → no sale. Sellers are going to be mad about being asked to take an unexpected hit on sales price right before closing as the buyers scramble to handle the last-minute-surprise costs (in your case, $8500 for rewiring plus the higher HOI premium). That's life, and lo que será, será, but it's a shame that this information will often have to be learned the hard way near settlement time. — ¾-10 01:02, 28 November 2007 (UTC)


 * I hear what you're saying, but I think this might be a regional difference. My best guess is that in areas where home prices are much higher than the rest of the country -- such as east and west coast -- insurance companies are (understandably) more stringent. I have had to move three times in the last five years, including last month. I just moved into a house with knob and tube and did not encounter any problems with getting insurance.  In any event, both your experience and my experience are purely anecdotal and original research and do not fit wiki guidelines for inclusion in wiki articles. I agree that something should be mentioned and I think the current edit fairly covers the issue. --John Ivans (talk) 17:34, 28 November 2007 (UTC)


 * I agree completely. I am OK with the current version also. There's evidently a lot of variability between cases, so we can't really say anything more than what is said there. Seems pretty useless to add a sentence such as "Anecdotally, the hassle involved in lining up coverage varies from great to none." So OK as-is. — ¾-10 23:07, 28 November 2007 (UTC)


 * It varies a lot. In my area virtually every home has K&T, and insurance companies are good with it (talk) 17:34, 28 November 2023 (UTC)

Locating Knob and Tube
Does anyone know how to locate Knob and Tube with a device from the interior? Or just any wiring in general from the interior?

If so you know where it is so you can put insulation in the unaffected areas. —Preceding unsigned comment added by 66.92.183.226 (talk) 01:40, 13 November 2008 (UTC)


 * If you run current through the wires (by turning on a light that uses them) there will be an elevated AC magnetic field throughout the area between the two wires. This can be detected with an AC gaussmeter or a magnetic pick-up coil connected to an audio amplifier (sometimes called a buzz-stick).  If there is a power line or other source nearby, it may be better to use a heavier load on the circuit, such as a space heater. Physicsjock (talk) 21:39, 23 September 2009 (UTC)

First sentence- copied from elsewhere or vice-versa?
While trying to find a source for the statement that K&T wiring is still permitted by the NEC in certain cases (I put a citation needed tag for now), I stumbled across an external site (http://www.nachi.org/knob-and-tube.htm) that starts with an identical first sentence to this article other than the end date being changed (1930s to 1940s) and a couple of words removed from (K&T). Which came first? Did they copy Wikipedia or the other way around? —Preceding unsigned comment added by Sfisher (talk • contribs) 15:36, 10 June 2010 (UTC)

Similarly, http://www.knobandtubewiring.ca/ is substantially similar to this article. — Preceding unsigned comment added by 199.246.40.54 (talk) 16:19, 27 February 2012 (UTC)


 * Regarding "who copied whom", there's a certain set of variations on the theme: The first two are the ones you'd suspect: (1) Someone adds content to Wikipedia by cribbing it verbatim (or nearly verbatim) from elsewhere, or (2) Someone adds content to elsewhere by cribbing it verbatim (or nearly verbatim) from Wikipedia. But then there are the cases where both sites are OK because one has been influenced by the other without being a copy of it. As the years go by we start to see more of this. It's pretty natural and inevitable, I feel, because any site that's trying to give a layperson's overview of a given topic is going to end up sounding more or less like Wikipedia, because by nature of its darwinian authorship, Wikipedia often trends toward a really good, concise, circumspect coverage of a subject—after which, no one can offer a similar explication on their own site without ending up sounding like Wikipedia a bit, even if they didn't mean to. In this particular case, I'd say there's been influence, but none of the sites is a "copy" of the other. But as years go by, it will not always be possible to trace the precedence, as most sites, unlike Wikipedia, don't have a "history" button that list timestamped previous versions. — ¾-10 01:28, 28 February 2012 (UTC)
 * The photos on the inspection site carry a 2009 copyright and the first sentence here dates back (significantly, in a slightly different form) to 2006. As for the .ca site, it's not even a good copy of this article, randomly adding "...in Toronto" in the text. You've got my word that I didn't crib someone else's Web site when I wrote in June 2005. --Wtshymanski (talk) 03:41, 28 February 2012 (UTC)
 * Yeah, that why the more-savvy readers go to "the likely source", Wikipedia, and compare. There are often "more pairs of eyes" monitoring the quality and updates (with the power to correct problems immediately), and Wikipedia timestamps and archives almost everything.  The theory of "convergent evolution" of writing has some validity ("Great minds think alike" 8^), but near verbatim text is highly unlikely to have evolved independently. Savvy readers know that websites which copy wholesale and claim the credit for themselves aren't likely to value the reader's welfare all that highly, either. --Reify-tech (talk) 05:34, 28 February 2012 (UTC)

Requested move 8 February 2015

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section. 

The result of the move request was: moved. Number   5  7  10:20, 16 February 2015 (UTC)

Knob and tube wiring → Knob-and-tube wiring – add hyphenation for good luck 76.120.164.90 (talk) 20:27, 8 February 2015 (UTC)


 * Seems logical--tentative support Red Slash 03:56, 9 February 2015 (UTC)


 * Support because those with knob-and-tube wiring need all the luck they can get. Also per WP:HYPHEN.  —  AjaxSmack   01:17, 12 February 2015 (UTC)


 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

AFCI / NEC question for the article
Arc fault circuit interrupters are now required for all new home construction in the 2014 NEC to reduce the risk of arc related fires, the most common cause of electrical fires.

AFCIs can also potentially protect old K&T wiring from arc fires. Is it acceptable to uses AFCIs with K&T? It would certainly seem to be the case, and AFCIs probably should be used to upgrade and protect old circuits where feasible.

If so, how would that work? Are screw-in fuse replacement AFCIs available? Are new circuit breaker panels with AFCIs permitted to connect to existing K&T ?

-- DMahalko (talk) 21:52, 24 November 2016 (UTC)

sentence in Advantages
"such porcelain standoffs carry far higher voltage surges without risk of shorting to ground" -- higher than what? If this is supposed to be a comparison to another insulation method, that method needs to be specified. Or is it just trying to say "carry very high voltage surges"? 2605:A601:4100:3300:2306:3E9B:EE82:C306 (talk) 00:16, 26 November 2016 (UTC)

Was this system used in Canada or Great Britain - regulations ?
Article says used in North America - Was it just USA or was it used in Canada too, and Great Britain ? - Were there any national or state wiring regulations 1880-1930's ? - Rod57 (talk) 10:12, 17 September 2018 (UTC)
 * Knob and tube vexes home restorers in Canada to this very day; my own home had a strange stray run of one wire run with knob and tube workmanship, I have no idea why. The US National Electrical Code originated in 1897, the Canadian code in 1927. I would be thrilled to bits to hear if this was ever a style of wiring used in the UK, though I'd be surprised if it was. There seem to have been a lot of patented schemes for enclosed wiring invented in the UK. --Wtshymanski (talk) 19:37, 18 September 2018 (UTC)

Disadvantages relevance
I'm sceptical of the relevance to 'K&T' of some of the 'disadvantages', especially 'never included a safety grounding conductor', which seems an orthogonal issue; it was rather 'was used at a time when safety grounding conductors were not', surely - there doesn't seem to be anything inherent in the system that mean you couldn't/wouldn't have a third tube for earth? If that passes as a disadvantage, surely 'single phase only' should be another. -- OJFord (talk) 15:00, 6 August 2021 (UTC)


 * I agree, these are disadvantages due to the age of most systems, not disadvantages of knob and tube itself. The article states that knob and tube can still be installed with permission, and these modern systems probably have a safety ground conductor. Many of the rest are affects of aging, not disadvantages of the wiring system. Tadfafty (talk) 08:56, 29 June 2023 (UTC)