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K&T wiring boilerplate.

Terence McCann

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Here's what I start off with:

The "knob & tube" wiring (insert location here) is the original wiring in the house. It is very old, is not grounded, and is no longer considered safe because of the unsafe wiring practices of that era, and because the insulation on the wires is deteriorating. A licensed electrician must be employed to replace the "knob & tube" wiring now. This will require a permit and will be expensive.

Then I tailor the comment to suit locations, amounts, conditions, etc. If I see K&T beneath the insulation in the attic floor, I make particular mention of that fire hazard.

Hope this helps,


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This is what I write if everything appears in 'working' order:

Knob and tube electric wiring was observed in this home. This type of wiring was standard at the time of construction, and unless otherwise noted appears to be in serviceable condition. Client should consult with a licensed electrician prior to closing to verify its integrity, and/or if expansion to the system is planned. Expansion or additions to knob and tube wiring normally are not allowed as it can overload the system and cause a fire hazard. Client should seriously consider updating all knob & tube wiring to today's standard of romex. Client must be made aware some insurance companies will not insure a house that has knob & tube wiring; we recommend consulting with your carrier (prior to close).

Of course there are other statements if it's covered with insulation or if additional splices are present.



Morristown NJ

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Has anyone, ever, found a house w/ K&T that wasn't full of jackwired silly crap splices and all manner of other problems? It's only OK if it is in its original pristine condition, not if it has been altered.

I grew up w/ the stuff, work on it all the time, & am finally @ the point where I don't cut any slack. It's ancient, outdated, likely dangerous if we could see all the various things that we can never see in the walls, ceilings, & junction boxes, & it's time to rewire.

W/ the average home price hitting stratospheric levels nationwide, is spending a couple grand to have new wiring really something that anyone wants to gamble on? I think there is resistance because it is hard to find a sparky who wants to do the work, it is invasive, it requires thought & planning, and several other things in short supply in the trades nowadays.

In an inspection world that has deemed AFCI's as necessary in brand new BR's w/ outlets every 12', GFCI protection throughout the entire house, electrical service cables that are >10' above grade, neutrals & grounds that are seperated after the main disconnect, no double taps unless the device is made for 2 wire connections, proper polarity receps, grounded outlets & fixtures, etc., etc., etc...., how can anyone argue for K&T?

Yes, even the esteemed Dougie H. sez it's OK, but you can't trust people from California about something like this. [}}:-|>>]

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Hi guys,

I'll dig out one of my boilerplate comments on K & T later. Right now I'd like to mention something that I see a lot with it - loose/disengaged knobs. I used to think it was just those particular homes, but now I think it is something else. [:-idea]

Has anyone ever seen a piece of wood with a smooth-shanked nail in it where the nail didn't eventually loosen up and walk out of its own accord [?] I haven't.

I think the nails that hold the knobs in place are working their way out and after more than half a century in man[:-boggled]y homes the halves of the knobs are just now getting wide enough apart to allow the wiring to fall free. [:-boggled]

Think about this the next time you're in an attic and see knob and tube. [:-magnify]



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I guess I've been lucky, the handful of times I've run across K&T it was already abandoned. I double-checked that all over the place, noted it for the report, and forgot about it.

Everyone has to measure thier own risks in this business every day. But I've said it before and I'll say it again...Electrical is a very bad place to stick your neck out. [:-wiltel]

Brian G.

Electrical-Problem Scaredy-Cat [:-skull] [:-shake] [:-skull]

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I remind people to consider the following relative to K&T:

-No 'equipment ground wire' present. ('less safe')(have boiler plate about what a ground fault is).

-Rubberized cloth insulative jacket is surely starting to get brittle (find some examples, point them out in photos).

-Meant to be 'free-standing in air (except where run through tubes...). Point out insulation packed around it... mention that some insulation installers actually will require it be removed prior to installing insulation. (some...not all).

-Point that by this time (approximately 100 years) the building has probably had renovations over time which increase chances of ground faults to occur (pipes run in chases, wires fished through spaces, 'stuff' (K&T) in walls and ceilings have higher chance of having been moved out of original intended position. The chances for renovations over time to have damaged insulation is likely higher.

-Mention that GFCI receptacles can be installed on K&T, but what if as soon as you do that and you energize the circuit, the GFCI trips? Now you have to find the GF...

-Some insurers will not insure a property that has knob and tube wiring. Yep....since 9-11.

I also mention the thicker gauge wire, etc. It all leads to considering 'pro-active replacement' in general. I also tell them that others may disagree.

I find that in most basements (like the one yesterday in a circa 1840 home) I can find at least one or two defects (in yesterday's case, I found a 'hot' K&T conductor fallen off of its knob, a severed, unterminated, live K&T conductor, K&T running against/on metal pipes and boxes and worn-away insulative jacket with exposed conductor.

Rarely do I find a 'pristine' condition installation though in some uninsulated attics, I have found some installations that looked almost as good as the day it was installed (but I didn't 'flex' the jackets...).

I have an antique book called "Electrical Railways" that shows how these installations were supposed to be installed at that time. They make good points about proximity to metal, free-standing in air, etc.

In the infancy of the electrical distribution system, there were many ground-fault-related fires out there...

Now with 'equipment grounds', 'bonding', GFCI, AFCI, the risk of fires due to ground faults and arcing is less. "Less is more" (safe..).

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