It’s so pretty to see a well run knob and tube install. Saw one in my friends house - like looking back in time…. And I tore all of it out of there! Way too dangerous. I did an extremely pretty rewire. Hopefully in a hundred years somebody will look at my install favorably, before they rewire it again.

You convinced me! My home is almost 90 years old. I think it's time.

It's only bad if it's in poor condition. That tends to be the case, but the people wiring homes back then weren't stupid. Those porcelain knobs and tubes will outlast most modern installations.

Knob and tube goes right along with balloon frame houses...both of which contribute to house fires a lot. Old wiring and an open chase from basement to attic. Seen it where a house was engulfed in flames in the walls and never set off the detectors. Fortunately the family got out safely.

One of the best explanations I’ve seen thus far regarding K&t wiring. You forgot TWO important things to add. 1. K&T is rated for 15 amps. Oftentimes folks overload it and that’s trouble. 2. Neutral fusing Back in the day they thought if one fuse was safe adding another to the neutral would make it double safe. The problem with this is that when a fuse does blow it normally takes out the neutral fuse leaving the circuit hot. Many an electrician in the day would tell you the end result of that. That is IF they made it. K&t is safer but the facts you mentioned and the ones I added are why replacement with modern wiring is an order.

I've only I've come across knob-and-tube was just one job. I was a bit amazed by the process it was done. I know very little about it because my time came well after in the 70s through today it was about two decades ago that I ran into it. It's a trip how they used to do it

Thanks for this great explanation. I'm looking forward to a similar list of cons with BX cable.

Knob and Tube systems had the boxes with a separate Ground wire clamped to the nearest water pipe (Lived in 2 houses with/had K&T). for Bathrooms and Kitchens, this was the practice. My Top Issue: folk working on K&T that do not know HOW. Proper K&T was soldered after doing multi turn wraps around the main line, then well taped.

I used to work fire/water restoration and a lot of home had this old wire. Even if the wire was unrelated to the fire the whole house was gutted and all the old wire and associated pieces scattered along the ground and wire into a scrap copper pile. All new wiring, outlets, switches, etc. Felt kinda bad seeing this pice of history from the 1800s just going in the trash but was unsafe.

My dad bought an old Audel's book on electrical wiring in the early 1940's that tells you how to wire with knob and tube.

Enjoyed the video. I am an electrical contractor and have rewired multiple homes in historic Richmond VA and you are spot on with all your concerns. One additional thing I constantly ran into was that it was common practice to switch the neutral wire in wall switches. Three way switching was done very odd as well. Great job keep up the good work!!!

Very good. Thank you. Insulation was my motivation to replace it, but fear of fire was important too.

A family member lives in a house built in 1916. The structure is original and some stuff remains from its original configuration. I wonder if there is still some parts of the knob and tube. I find it interesting how things were done in the past and the evolution of plumbing and electrical

Hey KES! Good to see you here on KZfaq. I reached out to you via email last summer when I was helping a friend on Cape Cod. We failed an inspection for not having an emergency disconnect for a 200A upgrade. Eventually I went back and the work was approved. Nice video!

My home is 93 years old and I’m currently removing the knob&tube in the attic. Fortunately, wiring in the walls is romex and the k&t is only in the attic. Unfortunately, there is almost a foot of insulation in the attic. I’m replacing in the walls where possible, as well, since it’s old romex and the rubber/plastic is pretty brittle. It is very slow going. The hardest part was getting new home runs from the basement to the attic. It’s not too bad, actually.

You need to come out to California, nob & tube wiring was installed here into the fifties and early sixties.

Thanks so much for a thorough discussion of K&T wiring. Because of all wooden and plaster-on-lath walls, I am concerned about the prohibitive cost of new wiring, in large part because of the difficulty of access and huge amounts of wall repair to follow. I don't think any contractors are able to make such repairs without costing an absolute fortune. It's a very large house.

Knob and tube on the left coast was installed at least up to WWII, not 1932 as you say. My home was built in 1940 and originally completely knob and tube; as an electrician I can tell you this is the case in housing throughout the SF Bay Area. Most homes still have a blend of knob and tube in the bedrooms with a fuse box subpanel and modern wiring in the kitchens, leading back to a circuit breaker meter/main. Because of the age of the housing stock, there are still a lot of FPE OCPDs out there which represent the first-gen electrical remodels that occurred in the 1950s and 1960s.

I ran into a gas pipe at a duplex unit that was hot. It ran outside of the building about 2 feet off the ground for 40 feet. I was working at a small apartment building across the alley and the heating contractor that was working at the duplex came over and told me he received a shock from the gas pipe! I was skeptical but went over and looked and sure enough I read 124 vrs to ground.😫 To make a long story short it turned out that there were no ground wires anywhere in the duplex, and and no bonding of gas and water pipes. The kitchen stove had a spark ignition and the neutral wire of the stove cord was attached to the stove frame. The outlet that this was plugged into had hot and neutral crossed! Made everything attached to the stove hot. How no child ever got killed playing out there is beyond me…. Moral of the story: Always hire a qualified electrician.

I told my professor in college where I was studying electricity that if I bought a house all knob and tube wiring was coming out no matter what and that the new wiring would, if possible, would all go in some form of conduit.

I was going around with a home inspector in 1994 through a house that I was buying. The house had live nob and tube wiring. He claimed that nob and tube wasn't so bad because the conductors were separated and there was no way to short them out by driving a nail. At that time I had no difficulty getting insurance on the house, despite the nob and tube. I didn't really like the fact that the house had this antique wiring, and I worried about the modifications that were made to the wiring over the years, for the house, a small bungalow originally had just one circuit, but now had many circuits using the nob and tube. I only had 5 grounded outlets in the house and an antique key switch in the garage gave me such a shock that I would replace the garage light with the circuit breaker off so I didn't have to touch the switch. Why didn't I change out the wiring? Cost! To replace all of the wiring would have easily cost 10 to 15 thousand dollars and I was a home health nurse paid Burger King wages.

i wouldn't say just because something is old it's bad, I still come across knob and tube that is still in great shape even in the light box, and to solve the no ground issue you can install GFCI receptacles. granted I'm partial to knob and tube, even installed it in my shed, fuse box and all. Biggest issue i find with it would be lack of circuits of course, and the insulation issue. i've actually load tested it, new plastic wire vs. 60's vs. 40's vs. K&T all #14 and the K&T won out easily, the plastic melting and burning up while the knob and tube didn't do anything even holding 90 amps. 60's wire still melted, 40's held on fine until it got so hot the insulation became conductive and the whole thing glowed like a light bulb.

My house was built in 57, and I have knob and tube. Greater Cleveland area though.

1935 house in California has knob & tube wiring. I’d like to get rid of it but need an electrician willing to do it. Had an electrician do some remedial work and add some circuits. The house is concrete block so he’s not thrilled about that. Insurance is the biggest issue…expensive…high deductible.

Thank you for sharing your knowledge.

Bought my 1920 all and I mean all brick lap and plaster home 3 years ago. A mechanic and hobby machinists the home runs a 200amp service with modern breaker box that converts to the k&t system. The garage also was k&t with 3 lights and one outlet. Also all brick. Rewired the kitchen the first year while doing a updated look. Rewired the garage the 2nd year to increase my productivity. This summer will be the attic and upstairs rooms. I'd like to get some insulation installed for next year. This house is a bit drafty.

Do a video going over issues with BX wire.

I live in Maine house was built 1940 and at one time had knob and tube still have some of the porcelain insulators in the basement

Excellent Video. Just discovered K&T wiring in my mother-in-laws house, as an insulation company said they wouldn't insulate the attic with it. House is from 1920, so it makes sense. The house if full of K&T. 1300 sq ft house 2 stories, what is a ballpark to replace it? Each bedroom has a single outlet(in the baseboard), so i'm thinking that each room should have more outlets as well. BTW, the house is located in Portland, Maine, a stones throw from MA.

Just ordered your knob and tube book bro...thx...👍

Another issue is overloaded neutral wires

I enjoyed this very much, Thanx. Had some exp with it, changing over to romex, a new panel was installed (service entrance equipment) weird stuff, small home and 12 fuses. they fused the neutral! I have seen this in old houses on Cape Cod on west Main street.

Thank you

Great conclusion

First time home buyer here in windsor Canadá. I just discover I have this type of wire and man I am kinda scare on how much it will cost me to get it re wire 😶 wishing I had the budget. But it looks like there is a mix of new and old.

LOL! The thumbnail caption totally has me ROFLMAO! Are fireworks safe? Is walking around a major city at night safe?

How does existing K&T wiring even handle all the modern appliances and computers and stuff we use today on old wiring that was designed for some lightbulbs and maybe a vacuum cleaner or something back in the 1900s I would expect that the wiring would overload pretty easy at that point and be a danger.

Comments: 1. If it's getting hot enough buried in insulation, then there's another issue going on. I have yet to see any evidence of a fire from an unmolested, normally loaded K&T directly caused by covering with insulation. Millions of homes had this done. 2. Insurance companies. No surprise. What's new? 3. Ok, lack of ground. Inconvenient. Yes. Downright dangerous. Not necessarily. Depends. In your case, an handyman hack, not an original install. 4. I agree with this. Was also an issue with earlier plastic Romex. If you have attic access, one method to fix it is put a plastic jbox in the attic and cut off the burnt section of the old wires and route them into the box, then do a whip with modern NM to the fixture. I would not call this "extending the circuit". It's a repair. Other than burnt insulation in fixture boxes, the K&T I encountered had insulation in very good condition. 5. Yes it's old, but so what? These installation were almost always professionaly done and made to last. If you need to upgrade, run new circuits from the panel, leave the K&T alone, unless the house is gutted to the studs. K&T was still allowed in the 1975 NEC, although most AHJs outlawed it. The latest house I encountered with this wiring was built in 1968 in rural CA.

Hi. I live in Massachusetts in a house that was built in 1903. If you go into the basement you can see remnants of some old K&T wiring. You can also see that the house has had the wiring updated throughout the years as well with both I believe that second generation wiring (has metal casing around it) and what I believe is Romax (?) wiring. Last summer I had the electrical service upgraded to 200 amps and converted from fuses to circuit breakers. I hired a reputable electrician that got the necessary permits etc. My concern for years was whether or not that old K & T wiring still powered any of the outlets in the house. After stumbling across this video I got to wondering if between the electrician and the wiring inspector if the upgrade would've or could've been allowed if the house still had active K&T wiring?? Your thoughts would be greatly appreciated. Thank you.

I've also read that common neutrals between circuits was done with some K&T installs, but that might be a regional thing. I have a 1915 house and some of the original K&T (with dedicated neutrals) is still in use for lighting circuits, with most of the receptacles having been replaced with separate AC (no bonding wire) or NM runs over the last half century. I think I have just about every generation of wiring in this house, although luckily aluminum is limited to range and dryer receptacles. I had no problems getting insurance, but everything was inspected before we bought the house.

Thanks will share

Knob and tubes do have their disadvantages- hidden behind walls and not protected but I also see significant advantages. Many are still in use- this proves their longevity. They are spliced /joined by twisting other conductors together soldered and then insulated. They are insulated with rubber and or cloth insulation, ceramic tubes and separation of conductors. They have the ability to dissipate significant heat because they are not confined hence they should be able to handle even more current. If they were modernized with a ground wire and maintained I think they will be on par with current wires. Today we have insulated copper wires that are extremely close to each other in a confined space wrapped with additional insulation- metal clad, or plastic- Romex. Tightly packaging the wires together lowers the specifications of it's awg due to fear of them melting and shorting each other.- hence another reason they add ground wire.

Yikes!! I’m in the buying process of a house with KnT wiring, but more in hesitant. I live in NM, this house is 83 yrs old with a newer service panel. What should I do??

Thank you!

Should people with K&T add arc fault breakers to make the home safer? What's the pros and cons to that solution?

I saw it in attic of one old building it wasn’t in use but i live in Estonia where you find maximum 60 year old wiring because people change it often i changed my entire home 2 months ago

Just being old isn't a problem. It's the degredation that happens because of that age that causes specific problems.

Replace it you can tap dance around this issue in the end it need's to be replaced .

In knob & tube did they just run one ceiling light wire down the wall cut it at the switch on the wall, and run the one wire back up where the junction +/- was located in the ceiling light?

I've turned down several side jobs because they won't replace the knob and tube

Over demand on the circuit is true nobody has microwave oven and modern appliances back in 1902

I don't know about electrical wiring but I was wondering if there could be a modern version of knob and tube wiring that is grounded?

I am in the process of buying a home with knob and tube wiring. The gfci's do not work. The seller agreed to have an electrician repair the gfci's. Can an electrician run newly updated wire to the gfci's and all of the appliances and keep the rest of the house as it is at knob and tube wiring. The home must pass inspection in order for me to buy it and no one wants to rip out all of the old plaster to remove the house of this wiring and install all new wiring?

Is there a way to insulate over the wire with plastic tube etc ? The original covering is gone.

Well. Some issues some lighting in series chain lights via single poles and switching neutrals via three ways . cloth. Romex . You had sometimes a color coded neutral Of course if you had a master electrician with the connections soldered. Than you it was no to as bad as other jobs .

Knob and tube is really the worst because it has 90 years of hack jobs and jank accumulated. If unmodified, it's not that bad for lighting circuits.. but your issues are valid for sure. Having no ground on your outlets sure limits what you can use, and having a GFCI on every outlet really only is an expensive bandaid that doesn't actually fix the problem.

With that rhetoric you should be a NEC employee!! The NFPA/NEC sells nearly $1,000,000 worth of publications annually! The NFPA employs 600 people??

👍👍

its actually a well thought out system other than no ground.....both conductors are spaced apart and connections are soldered together ...he is right about the wires being baked over the years from bulbs though......disintegrate if you look at it wrong lol

Why don't modern house wires need cooling too?

Easy bake oven in the 1980's only used a 40watt and you cld bake breads with it imagine a 100watt lol

This is nuts people don't want to change their electrical circuits to newer technologies - I just cannot imagine living in a house with live wires like that

Wow wow 😨

Between outdated wiring, lead pipes, no insulation, 120yo cast iron sewer lines there should be a superfund to help people get their homes updated..lord knows this govt has the money to spend on everything else

K & T is too old and never safe. It's just too old

WTF for me as a german that is absolutely ridiculous. Do this wires even have some sort of insulation or is it just the bare copper running on the ceiling

It definitely not as safe as today's electrical wiring.

Was it called the Jewish electric? I graduated in 1977 from high school school as electrician... obviously I ran into this tubing and from older electricians, they called it, Jewish.....

is knob and tube safe let me see house from 1902 and still hasn't burnt down