My grandfather worked for Penelec in PA, all his life and retired in`1965. When I was a kid, probably in 1967,68, I remember him telling me that after a heavy thunderstorm, back in the 1940s, someone called and said they were out of power. His crew went to the house and found power was available at the entrance. They went inside and there was no power. They started testing and found none of the knob and tube lines had power, he grabbed one of the wires and it fell apart, there was no copper in the insulation. They checked the whole house and most of the copper in the wires was vaporized by a lightning hit during the storm. The people needed to get their house totally rewired.

"They made things to last." What a concept, produce and use quality material and items and here a hundred years later they are still working just fine.

I actually learned how to install knob and tube wiring when I was in vocational school in the 1960’s. I think it was just a way to introduce us to something we’d find out in the world, as well as to visualize circuits. Very cool.

In "my days" in HVAC/R service, "the boys" were installing a retrofit system in a very old farmhouse. I was up there installing the AC tubing/ controls and part of it was back in a closet against the roof pitch. One of the guys says "what's this wire here for?" BARE WIRE. One look and I grabbed my meter. YUP!!! Still live, still being used. BARE knob and tube This was about 1985-90-ish

My grandparents had a home from the late 1800's that originally has gas lines running through the walls for gas lamp lighting.

I remember my great grandmother’s house had this type of wiring around 1960. The house was built around 1890 something. There was a hand water pump at the kitchen sink, and a cistern outside to catch rainwater from the roof. The cistern was divided through the middle by a wall of brick, two bricks thick. The water came into one side, and the brick wall acted as a filter. The water was drawn out from the opposite side from where it entered. The house had lathe and plaster walls. When she passed away, the relative who inherited the house had it gutted and brought it up to code.

as an electrician from 1967 to 1995 i've done a lot of work on knob & tube wiring. if it is left alone & not "messed with " it is perfectly safe, however, this is rarely the case. i spent a lot of time re-wiring buildings to remove knob & tube for nervous insurance agents & homeowners. my house was built in 1906 with knob & tube. i sleep just fine. from 1995 to 2017 i was a electrical safety inspector for a major ohio city. better inspecting than working on. most of the time needlessly. if knob & tube is inherently flawed, most of the houses in oakwood, ohio would have burned to the ground years ago.

Superb and simple explanation of early wiring technology - have seen it many times. My dear old dad was an electrician - finished his apprenticeship at Standard Telephones in England in 1919. After a spell in the British Army in India (1921-1933) in 1933 was employed by the Mount Royal hotel in London until his retirement in 1980 - having worked as ‘sparkie’ for 47 years. Electricity in all its forms is maybe the greatest modern invention.

I grew up in a Philadelphia rowhouse, the third floor was never rewired, it still had the original tube and knob, their was a junction under the floorboard in the hallway on the third floor,it looked as good as the day it was installed. However, my house was built in 1900, and wired in 1911 for electricity, according to the city records that I found in city hall. The city back then required that any modifications made to a pre existing property needed to be doccumented.

Knob depth of 1" was good at keeping blind screws at bay too. Pound a nail in a wall to hang a picture. Boom. It was also nice to see the layout work, with both the hot and neutral running in the same void (plenums) between studs and trusses, but at the same time opposite each other on different studs. Professional electricians at the time, always kept the hot on one side, (I believe it was north or west), consistently throughout the house for reference

Many years ago , We rented a house that was all knob and tube , and our electric bill was around $16.00 a month . that was in the eighties .

Tube and knob was a well engineered concept of wiring, the wiring itself stood the test of time, it was Nickel wire covered in rubber then cloth wrapped, and then placed in a loose casing of burlap tubing, I have seen where rodents ate this insulation, this caused numerous fires back in the day im sure. Great piece! I will subscribe.

Back in the 60's my grandfather dynamited stumps to clear a part of a field. In the 70's ( after he died ) they found his stash. 3 sticks and blasting caps wedged between the sealing and the wiring of an old shed. Yes it was safely removed. As a side note.....Yes it was fun watching the stumps go up into the air. Down side was cleaning up the mess.

Even today, where K&T is frowned on and frequently removed when encountered, it generally works well as long as you NEVER TOUCH IT. As a service guy, I hated opening a box up and moving the old wiring around. As long as it just sits there and isn't moved it's really not an issue usually. But when you move K&T around, you find that as it moves the rubber insulation crumbles away and the woven sheath falls apart, leaving the conductor bare. Had to many a times apply heat shrink tubing back over the conductors to give it some form of insulation again. Best to leave it be if at all possible.

The house I grew up in had the remnants on knob and tube but had been “upgraded” to the two wire, tar and cloth cornered cable.... like Romex, but worse.

My family had a house that was built in 1903 at least that's the only records we could find of it. It had knob and tube wiring that still worked in the 1970's. The house also had a barn in the back yard with spots for 2 carriages and two horses with quarters for a stable boy above it. FLY NAVY!!!

Working on a bathroom renovation in Hewlett- New York about two years ago, 2019, saw knob and tube wiring running to the attic. Was told not to worry it was all in disuse for years. Put my tick to it, yep,still live running the attic light. My daughters house in Patchogue New York, around , five years ago, 2016, when the sheet rock was removed on the second floor, found the knob and tube tied into the Romex wiring behind the walls

Praise be to the mighty algorithm for bringing me to this video from eight years ago. Many thanks given oh mighty algorithm! The video was enjoyed.

dad and i rewired the house (built 1899) before i left for the marines. everything was on knobs as far as i remember. dirty works crawling through all those dusty spaces.

I know this video is over 100 years old. But it’s pretty good. Very informative.

Bought and lived in an old house in 1989. It had modern wiring but there were a couple of the old knobs in the basement. Now I've seen what the old system looks like.

The building which handles my data center actually still has some knob and tube in service, still in good shape. Maybe some day we will replace it. Then again we said that 10 years ago too.

A couple years ago my childhood best friend and I inspected his (recently passed) grandparents' 1905 built home. The house had virtually no updating since being built. In addition to the K&T wiring, the outlets were mounted in the baseboards down at floor level and it had mercury filled push button light switches throughout. It had a screw-in fuse (4 of them!) circuit box. Everything still worked as designed, and probably would have kept on working but it needed (and got) completely gutted out and rebuilt.

Old switches were soo cool

Had this open wire in my mom and dad's house for years. As a kid with my brother involved in CB radio I always thought it was antenna wire. Until my Uncle dropped a test light over them and it worked. Needless when he found out the wires were live it was removed that night. But for 50 plus years it kept the lights on. On our front porch. Scary!

I remember the nobs and tubes but the wires in our old house had almost no insulation left on them. Dad replaced them as he could but they were there long enough for we kids had plenty of time to find them in the attic as we explored our first home.

This comment section is a goldmine of history! :3 Love to see old technology like this, too! My fingers tingle just looking at it, but it's beautiful!

Here, over a hundred years later, one thing hasn't changed. Electricians still sit around in chairs discussing work rather then doing it.

The house I grew up in was built in 1941. We had the ceramic round knobs in our attic. The wires had that woven fabric kind of material on the outside of it.

Wow, I my dad owned a house in Fernandina, Beach that was filled with this knob and tube. He has since sold the place.

So informative! Never knew what these porcelain pieces were for!!!

So this is a good video. Have a funny story. I do maintenance at some apartments in oakland and recently they did a seismic retrofit ordered by the city. Unfortunately one of the wires was damaged between 2 of the lights requiring the wire replaced. This building was built in like 69 after knob and tube was no longer allowed in New construction. The city inspector came and said that we had rewired everything without permits because this year building came with knob and tube wiring not romex wire. The owner is a close friend that I also look out for since her husband passed away so I called the city about it and told them what the inspector had said. They looked up the information on the building to confirm what I has said and sent a different inspector to check everything. Told him why some wire was replaced and he just looked to make sure the boxes were bonded to the ground and said good job you passed. First inspector was written up and made to attend some kind of training again. I'm not even a electrician and I know the basics.

Many of the original Edison lightbulbs still work because the filament is much thicker than filament used in today's incandescent lightbulbs. That made them much less efficient (and bright) but far more durable. Interestingly, traffic lights of today (except for the LED ones) use a similar trick of thicker filament so that they don't need to be replaced very often, even though they use slightly more energy.

It wouldn't surprise me if Edison was the first to market porcelain insulators for use in lighting circuits, but he didn't come up with the idea; these were already in use when Thomas Edison was a child (back in the 1850s) - primarily on telegraph systems but also in electrical experiments alongside glass insulators. Just worth noting as a lot of people will interpret this video as "Edison invented porcelain insulators" just like many people think Edison invented the incandescent lightbulb. It's amazing to think that the first sets of wiring regulations/codes came out in the 1880s. What we call the "First Edition" of the wiring regulations in the UK was in place from 1882 (we're now on the 18th edition), and New York had regulations from 1881 (with the first US national code in 1897).

I have a modest collection od early Edison/G-E, Westinghouse incandescent carbon and early Tungsden light bulbs. I have a few Wert Dimmers as well. The Wert Dimmer when used with a 40 Watt light bulb which was the recommended wattage max for the dimmer, still heated up extensively, it felt like an iron. There was no limitations, their was no Underwriters Laboratories, and many homes burned down as a result.

I worked on stuff older than that in Chicago; conduit made with bare wires laid in grooved lumber with a slat nailed over the top!

My mother bought a houseboat in Seattle that had knob and tube wiring. Since she needed to upgrade the power to the house, she hired an electrician friend. He was perfectly willing to do the job, but he normally worked on commercial buildings, he rewired her houseboat to commercial code.

there is a house not far from were i live that was built in the early 1900s and was wired with knob and tube at the time it was built 4 years before power was run into our village they knew electricity was on its way and planed ahead as far as i know all of it is still in use today and in excellent condition along side with the modern wiring although all 4 original circuits were are arc fault protected with modern arc fault breakers a few years ago after the 60s 60 amp entrance was replaced

I had my 1905 home remodeled and I saved some of the knob and tube as a display. It's funny how the main house was knob and tube, but the garage was stab lok . The garage was built in 1954. Both were updated, but I never realized how expensive electricians are.

I love old construction materials

Super video. Such a prevalent system even has a modern way to connect to it. By using a metal junction box, you can put ceramic tubes in for the knob and tube wires, and clamps or connectors for Romex or conduit. 💙 T.E.N.

I know a couple who had a house that was built early 1900's. He cut away part of a wall and put a picture frame with glass, his window to the past, showing the bare wire wiring system.

The house I'm working on now is loaded with it.

fascinating. I still have the glass cabinet fuseboard from my gran's home.

4:17 Holy smokes, a cutaway of a GE MS-5001 gas turbine unit. I worked on plenty of them all over the world. It doesn't have knobs but it had crossfire tubes.

These arrays actually worked okay. One of the classic problems was people putting metal clothes hangers over the wires. Seemed like a convenient place to hang wash, but the insulation didn't hold up well over time.

Iv'e seen these in old houses with no insulation on the wires. If you wanted to add a light or an outlet, you would just twist the wire to the line and tape it. You could attach a new circuit anywhere along the line. Kinda scary but cool at the same time.

I'm a service electrician living in a 1936 home. Still has knob and tube wiring. Only real issue with it is that the insulation will begin to crack and leads to open copper in spots.

Retired from 45 years in the electrical trade, I live in a 1940 house that still has a little knob & tube upstairs. I’ve always felt it was designed to take aging and degradation of insulation into account. Properly installed knob & tube will work if all insulation falls off the wire and it’s bare, just don’t touch it! Knob & tube often fares well in floods, due to taking the “up and over” route, usually running in attics.

My Grandparent's house built in 1900 had it (later removed, can still see the holes), and the 150 year old house I lived at in college STILL had active knob and tube in the basement when I left 12 years ago.

I still have this in my house, as someone who learned electrical wiring in 2018-19. I HATED replacing switches in my house, I was so irritated by no neutral wire and ground wire in every box. The breaker box is even more of a nightmare since multiple rooms are on the same breaker, my bedroom is on 3 different breakers.

The history of electric power is fascinating. I shudder when I think of how insanely dangerous it must have been for them to be testing and learning things for the first time. No doubt electrocution and fires were common.

My house still has this type of wiring in parts of if and is in use daily and is running everything just fine .

Just south of Edison’s Menlo Lab (in Metuchen, NJ) saw old house with a seemingly odd glass panel on an otherwise time-appropriate (old) wallpapered plaster-and-lath wall. It revealed the original knob and tube wiring as 1 of the first homes to be electrified.

Wow they used to use a lot of porcelain back in the day. Looks like plumbers toilets weren’t the only items using the stuff.

In Canada, back in the 70's, there was still a section in the electrical code on knob and tube wiring. It was in recognition that it was encountered in the field, and provided rules for repair and splicing into it. Others here have commented that rodents liked the insulation. I have never seen rodent damage to K & T. I have, however, seen the insulation eaten off the later paper and tar "Romex" cable - right down to the bare wire.

I have actually worked on this stuff in my early years as an electrician

the house i'm living in, and running this computer off of is useing knob and tube, love that method tbh.

The paper is used as a spacer/gap filler to keep the conductors from shifting or kinking when the cable is bent. The nylon/PVC jacket on the conductors is the actual insulation, although paper is a decent dielectric/insulator if used properly.

Those cleets and knobs wiring looks almost exactly like what i found a couple of years ago in a cellar here in Germany. Still in proper working condition even with an original carbon fibre bulb, though way out of code since the end of WWII. But what do i care? I'm a plumber not an electrician. ;-) Edit, typo.

And if you buy a house with knob and tube, the insurance companies will freak out and may refuse to insure it until it's upgraded.

very cool, thanks for the video, I have knob and tube and trying to figure out what goes into rewiring, video was very helpful

Definitely an interesting demonstration. I've seen lots of K&T wiring, some still in good condition and service, but never have I seen those cleat things.

cool stuff, I'm curious how the switch actually works.. And its really awesome they are getting this info put together while its still possible.. another 30 years and it would probably just have to be all from book and no first person stories.

There's a place I have visited on the NY / PA border along the Delaware River that is now a campground but was once a grass airstrip. The original hanger still has this exposed wiring, although most is no longer in use. OTOH, last I looked the original fuse box was still hot. Up near the ceiling there are wires running the length of the building (at least 75 feet) kinda like a clothesline. It may have had more support at one time. These wires are about 10 feet apart and have the remnants of twisted connections, as if there may have been a series of suspended lights at one time. Guessing one is hot and the other is neutral, and you could just twist in another light fixture as needed, wherever you wanted. The reason I was there was to figure out how to disable those hanging wires. It wasn't too hard to follow them back to the panel and do away with the circuit, so nobody got hurt.

Some years ago I had to go into the loft of an old country house here in the UK and the wiring in the loft was bare copper held in cleats some porcelain and others lignum vitae, this dated from when the house had its own low voltage DC lighting set but at some time in the past the mains was laid on (250 volts AC) the downstairs wiring was modernized but the loft was not but it had been connected to the rest of the house so that there was a lamp up there. I went straight don frm the loft and pulled the fuse before I would go up there again.

Knob and tube was very safe for it's day. The wires never come together except at the device. The drawback is the coating and the fact that joints were soldered together. I've found places where the joints between wires failed from the solder melting away.

i grew up in a house built in 1907 that had knob and tube wiring and there was nothing really wrong with it except that it was a 3-story house with a 60-amp service and only 1 or no wall outlets in each room.. the house also had no insulation in any of the walls, so we eventually replaced all of the wiring with romex and a 200-amp service with plenty of wall outlets everywhere and breakers instead of edison-base fuses which were getting hard and expensive to find. the insurance company was happier and the house was much more liveable afterwards.

my nephew still finds this in his renovation jobs to this day. It's nightmarish. Many fires have been caused by this stuff being left in service.

My house still has this set up

Very important for the insulators being glass to be reused after the fire!

My grandfather’s cottage still has this wiring in use in the original part.

The last house my mom owned had knob & tube wiring in the attic. 1949 to today and no problems, but when I was young and had a reason to go into the attic I had to be very careful. I think I put some insulation up there.

*Knob and Tube = Bzzzzzzt!!!* Especially if the house was 80 - 100 years old and those wires sagged enough to touch from over-heating by modern appliance or broken insulators. In the daze of radio and lightbulbs, less of an issue. I still remember houses with thoze screw in fuses some people would sometimes replace with a penny, dime, etc. = Bzzzzzt, Fire!

As an electrician I have never had a call on a problem with knob and tube wiring. People see it and freak out but it’s probably one of the safest wiring methods

Knob and tube wiring is still covered in the NEC. ARTICLE 394.

I know homes this still exists and operable. Made to last for sure.

To place a ceiling light there was a 1×4 backer board between two joists laid flat with with 45 degree holes drilled next to and opposite each other to place the wires in, using pieces of loom to go through the board and lathe and plaster.

i got really into this and i clicked on it by mistake. thanks for the video

The building I live in now was knob and tube. There's still some in use but it's mostly been replaced with romex and 14/3 wiring.

Some of the insulation was asbestos, and would last forever. Mice love that rubber and fabric insulation. I lived in a house that had knob and tube insulation...one weird thing they did was put a fuse in both hot and neutral. If the neutral fuse blew, the light went out, but if you came into contact with live and ground, you'd know it. As long as you don't overload it ( by putting a 30 amp fuse in a 15 amp circuit, and the wiring isn't rotten, the knob and tube stuff is probably fine. One place I lived in back in the '80s was wired in 1922, and it was fine. Wall outlets had been added in the '30s. Originally, it was just wired for lights..

still the best today

An interesting topic that stopped far too soon

if you have an old house with knob and tube still intact leave it. if you want higher loads run a new electrical panel with new outlets and just leave the k&t for the already existing stuff like light fixtures. it is perfectly safe.

I actually have 4 way key switch in my electrical box, as well as a 15 amp knife switch

A good post, ive run into knob and tubing wiring, years go.

The owners of Exxon in Asheville North Carolina had this wiring in their house and they had red horse hair insulation in the attic they also had the first air conditioner unit installed in North Carolina posh house .

I bought a building in 2000 in the stairwells the lighting was still wired that way.

great video...very informative

. Edison ran a DC system I believe.. Seems like for a while before a National Grid every power station had their own power values and that if two companies wanted to trade power they needed a set of Motor -Generators or Rotary transformers to convert to the others standard. 110 volt 25 cycle seemed to be the popular one when a national grid required a national standard until the early 1950s when 120vac 60 cycle became the standard.

Thank you for the video.

I live in a Philadelphia townhouse right now and it STILL has knob and tube wiring. Some electricians act like it's a disaster waiting to happen, but if you really think about it, it's a system with multiple safety redundancies and will work indefinitely if undisturbed.

Why didn't they want the wires touching the wood? Was it due to heat from the current? It couldn't have been too hot since he was touching it with his bear hand.

Very concise and well explained

Fun fact - Knob and Tube is still in the electrical codebook.

If it had a ground and plastic insulation that didn't degrade this would be even safer than the way romex is run.

It’s like they used porcelain insulators to keep the wires free floating from everything. Much different from today wires are stapled directly to wood lol. I assume the difference is the conductors insulation today is more robust.

My house was built in 1939 and has this type of wiring it is visible in the basement.At first I was disappointed that it had this type of wiring but then I read that this type is safer than modern wiring.I think the only reason they stopped using it because it was harder to install than modern wiring.

Did alot of knob and tube work. In attics, you can't insulate oner the old wire, we would put modern wire and junction boxes. Reused the old wire in the wall. Very confusing work sometimes

great stuff - thanks.