Hello
My wife and I had a home inspection for a house were under contract and the home is said to have some knob and tube wiring. The inspector didn’t bring this issue up with us but it is present in the report
The report says “the structure is wired using romex. The house has existing knob and tube wiring in use”
It also has a picture of what appears to be knob and tube in the crawl space but no wires run thru the support. And to be honest I’m ignorant about electrical. The home does have a newer breaker box (2017) and updated 150 volt (1999)
Unfortunately this was not discussed during inspection.. only on the report. I do not know how much of the home is on k+t and I’m not sure what to look for. I’m worried about the safety and insurance on the home. I know this is expensive to fix
any advice is appreciated
Thank you
Replies
Knob and tube is very dangerous. The insulation on the old wiring gets brittle and is likely to come off exposing the wiring. There is no quick fix. If the knob and tube has been replaced in the walls then doing the accessible attic shouldn't be too bad. You say your main panel has been replaced. (I assume you mean 150 amps not volts.) If this is the case you may have arc-fault breakers. If not you should replace the breakers with arc-fault breakers. You will be safe from fire but if and when you have a problem you will then need to replace the knob and tube. Arc-fault breakers are about $40 so this is not a cheap fix. They were mostly required in 2017 but retrofits for the service upgrade weren't.
Personally I think the concern over knob and tube is overreacting on the part of many people. The wiring is most likely to only be a problem in light fixtures where the heat buildup from oversized light bulbs has degraded the wiring making it brittle or where taps have been made extend a circuit after the original installation of the wiring. Electricians deal with this all the time. Find a reputable one familiar with old houses and their wiring and they can probably offer some suggestions. The bigger concern is the use of three pronged outlets on the two wire knob and tube that gives the impression of a ground. This is unsafe but is solvable with the installation of ground fault outlets. A job for a pro. I wouldn't loose any sleep over any of this. If a real hazard existed, it would have surfaced by now. Also the lender would not have approved a loan. Nor would the inspector have risked a lawsuit for not mentioning an obvious dangerous condition.
From what I hear, a large part of the nightmare of knob and tube is that it's not wired up in a consistent pattern, it may as well be a spider web snaking through different walls and ceilings with a shared return.
From WP: "But with old K&T, a past electrician might have reasoned as follows: "I have a 20 amp circuit on one phase over here, and another 20 amp circuit on an opposite phase over there. Rather than run an entirely new set of wires for this one device, I will just tap off the supply wires of those two circuits and bring them together for this one device." This method of wiring does work and it reduces the amount of wire used, but it makes electrical problems very hard to find and fix, with (possibly undocumented) wires going all over the place within the walls and ceilings, to whatever was the most expedient supply or return wire at the time of installation."
Vishnej - It may appear that way to someone who is not an electrician but you have to remember they were skilled tradesman proud of their work and what you describe is not something i've ever seen with almost fifty years in the trade. It may appear that way to you if you aren't familiar with the wiring methods but it was not that haphazard or chaotic when originally installed.
I want to throw my two cents into this fray. Some 12 years ago we bought a 1947 vintage house with some knob and tube, some contemporary cable and a newish breaker box. During the remodel/update, we had the electrician replace stuff that was not up to code or at least make things safe. After all, insurance or no insurance, who wants a fire? And who wants to stay awake at night worrying about a fire? Electricians might have a hefty hourly rate but a good one can run in a lot of cable in a short time. What we couldn’t correct with a reasonable outlay was the complex circuitry that had accumulated over the years – several rooms had outlets/fixtures on as many as 3 different breakers and some breakers served more than one room. The need for an efficient way to find the breaker for a particular outlet/fixture was pretty obvious. For each floor, I printed out a simplified floor plan on an 8x11 sheet. On each floor plan I numbered each outlet/fixture by breaker number. With these plans taped to wall adjacent to the panel, it’s quick and easy to see which breaker to throw if work is needed or there is a problem.
I have rewired houses because the insurance company inspected the house and wanted elimination of all knob and tube wiring and upgrading Edison base screw-in fuses to circuit breakers. They raised the insurance several thousand a year until the job was completed. The new wiring included GFCI, shock protection in many locations and AFCI, arc protection, depending on the jurisdiction. Also, when insulation is added in an attic, knob and tube must be replaced because the added insulation can make the old wires overheat.
In the hope of provoking someone into saying more on the subject of home inspection and home inspectors, I am throwing in a follow-up comment.
After we had signed the purchase contract, the seller’s agent brought up the subject of a home inspection and happened to be able to recommend a good one. I had previously contacted another home inspector and upon mention of his name, I detected a look of panic and displeasure on the seller’s agent’s face. It was pretty obvious that my chosen inspector was one that she did not have in her pocket.
In this whole home-sales circus with buyer’s agent and seller’s agent, there is the insane situation that the buyer’s agent has no interest in a reduction of the sale price. Hence, an inspection that brings to light deficiencies that would lead to a reduction in the sales price is the last thing that he/she wants. (‘Brings to light’ of course refers to deficiencies that the seller did not list in the Disclosures report.)
With specific regard to home inspectors, and this might vary by state and locality, but my information at the time (for NY State) was that if the inspector fails to report a deficiency that leads to extra costs for the employer, the inspector’s liability is limited to the amount of his/her fee.
Theoretically, the buyer can get a reduction in the sale price if the inspection brings to light deficiencies not in the disclosure. That might come true in a buyers market.