The Deadly Chicago 3-Way (Only 2 Wires) 

Video Links here>> California 3-Way - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-AeXFe5ghmKQ.html Standard, Dead End and Single poles Switches here>> ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-B6gfI73Tvg8.html

Retired Electrician, Worked around the Washington DC area and fixed a few of these in older homes. We called them "Lazy Susans." Met my wife on a service call to repair one, I was the third electrician she called, everything was pulled apart for the remodel. First two walked away insisting there was no way that it had worked before. I bet her dinner that I could fix it in 20 minutes (4 gang box of switches). We had Pizza - she paid.

This was not the video I was looking for when searching "Chicago 3 way", but I watched anyways.

We bought an old house in 1981 and I, a young guy knowing the rudiments of residential knob and tube, was rewiring a 3-way on our stairs with romex when I discovered a light fixture off but both terminals hot. After calling my father, we tried to draw it out but failed. Then we called my grandfather, a longtime lineman for the regional power company. He drew it out for us and, as I remember, it was just as shown here. I've wired up numerous houses over the years but have never run into it again. Thanks for a great video.

This could not have been explained clearer or better. Nice work!

The same circuit was also used in Germany (of course it is also not allowed anymore nowadays). We call it the "Hamburger Wechselschaltung" Which would translate to the "Hamburg three way". I find it funny that you also name that after a city. But here it was also not only done in Hamburg. I remember whitnessing my Grandpa getting an electric shock from one of those things when he was changing a lightbulb which was turned off at the time.

This is KINDA ingenious in that it makes the XOR operation by inverting the lampholder polarity for the two ON states and double-hotting or double-neutraling it for the OFF states. Back when I studied the topic, this was not even given as an option. We were taught straight off to make the "hallway switch" by wiring hot to one switch, connecting the switches through the travelers, then taking the lamp hot from the other switch. And in a 230V country I can readily see why this was not even an option.

I work in Chicago, I've run into this once every year. It amazes me that this problem is still out there.

Retired electrician. I have run across several of these 3 ways. Usually they don't have power run between the switches. Instead, switch 1 gets power from receptacle 1 and switch 2 gets power from receptacle 2. This worked OKish when we had single phase 2 wire services, but when you upgrade to 3 wire 2 phase electric services, you could have the switches on different phases and send 240 volts to the bulb. I knew this as a farmer's 3 way. I learned about them early in my career and made money fixing them when other guys were confused.

About 15 years ago I ran into something similar and my boss at the time got mad at me for not being able to figure it out and make the repair. I've been through school in both the Navy and an accredited DOL-certified vocational school and now I'm a licensed electrical contractor and I'm still baffled lol. Great explanation through and I guess it's good that I dont understand it because its a dangerous way to wire lighting and receptacle circuits. Great video!!

In 30 years of doing electric work I've 8:02 only seen this one time in an old knob and tube home we were rewiring. My boss at the time called it a switched neutral 3 way and showed us how it actually worked. Very cool to see you describe it with such great detail.

When I was a kid puzzling out how electrical systems worked (based on my experience of wiring up a train set), this is what I came up with for the 'magic' of three way switches. I thought it's how they all worked until I came across my first standard three-way, which was very confusing to me at the time based on my Chicago assumptions from childhood.

Finally, an answer to why I always got zapped as a little kid, visiting my grandparent's 1940s vintage home in south suburban Chicagoland. Usually happened when getting out of the bath and flipping the switch with a wet hand. I bought a house in 2011 and had a lighting circuit that was wired Chicago style. Had it fixed immediately. Frankly, I'm surprised the inspector passed it but I live in AZ where building and zoning regulations are just a serving suggestion.

I've watched a lot of three-way videos, and this was by far the most informative!

I’ll never forget my first experience as a young apprentice. Homeowner already took it all apart to replace switches and marked nothing. I was unable to figure I out because I was trying to think competently on something that isn’t competent. I assumed the homeowner didn’t realize that the 3-way never worked properly. I later questioned some old timers that explained the dangerous system to me. Glad they did because I’ve run into many of them. Two of them that stand out: 1) this setup with a 3rd switch location (using a 4-way switch) 2) the two 3-ways were on different circuits, both on the same phase. It would be pure luck on a service upgrade or panel change to get them on the same phase Great Video! Many have never seen or heard of this!

Wish you’d been my apprenticeship instructor 45yrs ago. Great explanation! 👍🏻

I found this chicago 3 way in a 1920s farm house here in Denver. the home owner changed the switches but got the wires mixed up. I figured it out and got it working so my recommendation. if you change the switches pay attention to where the terminals are on the old switches and on the new one(especially the common).

I thought I have seen many funky things in my 30 years of electrical work, but this Chicago method has now gone on my top 10 things to look out for.

This principle is used in some bidirectional power converters, as well as solid-state on-off controllable AC switches - unlike triacs which you cannot turn off before the next zero crossing. Simple, yet effective.

I work on many older homes in Chicago. I am currently (pun intended) ripping into my 1914 home with layers of insanely bad wiring. I've got one 'circuit' somewhat like this. I've got a degree in EE, and figuring this place out is insane. I've got a Klien ET450 tracer and am shocked (yes, pun) at where someone(s) ran lines over the years.

Retired electrician, mystery solved. I have run across this 30 years ago in Denver, really never understood til now. It's always bothered me that I didn't understand, GOOD JOB!

First, thank you for your service, fellow Air Force. Electrician for 40 years, never heard of this dangerous situation.

We had that in our old (1912) family home, BUT SW1 was powered from a fuse box in the basement, and SW2 was powered from a fuse box on the second floor! Another problem occurred when we replaced one of the switches with a 3-way dimmer switch- the new dimmer switch immediately failed, it was apparently make-before-break and shorted the power ! That would not be a problem with today’s wiring methods.

This is both brilliant and kind of terrifying! If I ever find myself a homeowner again, I'll be sure to be aware of this setup!

Well done! Bravo! I have tanfled with these before and it took me a few hours to figure it out. I have also seen solid CU MC using the metal cladding as the traveler, once. That lit me right up!

That was an excellent video and explanation. I came across this after the home owner had dismantled the switches during his remodel. The home owner insisted that the three-way switch worked and I, of course, didn't believe him. I tried to understand how this three-way could have worked but failed miserably. I ended up rewiring the switches but I was always baffled by that scenario. Thank you for enlightening me after like 25 years. lol. This was a 1940s house in Queens, NYC.

This reminds me of lamp cord replacements. I've seen several with the polarity switched, leaving the screw shell hot all the time, including when the lamp is off. Always good to do a continuity check to make sure the screw shell is connected to the wide blade on the plug.

Thanks for the upload, guess it was worth the wait. Didn't realize this was known as Chicago 3 way, I'm assuming this method was designed by the Chicago Outfit to electrocute their victims instead of using a Tommy gun, which would draw more attention to authorities vs "deadly encounter with light bulb " lol😊 Joking aside, I actually ran across this 9 years ago on a farm in Sanilac County, Michigan. The farmer, who my father has known for many years, had 3 way switch in the house and barn on different panels, barn style yardlight on a pole near the barn, and single wire from the house and barn to the yardlight, installed sometime during early 50s, when the farm got electricity. The light sometimes got super bright for a couple seconds before going out with a bright flash that cracked the bulb, and the trouble began when the farmer purchased a 240 volt air compressor and needed to move some breakers around in the barn panel to make room for a 2 pole 20 amp, and unknowingly moved the circuit for the yardlight onto the opposite phase, and putting 240 volts on the light instead of turning it OFF in one of the four switch positions. Because I was 25 at the time and volunteered to try and figure it out while just beginning my apprenticeship, and explained to the farmer what he did in the panel and how I got it working normally after scratching my head for probably a couple hours, he took me out to dinner at a very fancy Italian restaurant. I personally found that very educational and rewarding to figure out with no help from anyone or any electricians books.

As an apprentice, I found this video really helpful. I've dealt with knob and tube before, though I've never seen a three-way switch in such homes. Now I do! 😊

Honestly everybody talks about the danger of the way things used to be wired, but I have a way to go about it that has kept me from getting killed. 1) Assume everything is hot until proven otherwise 2) Don't touch anything 3) Avoid being grounded 4) If something must be touched, do not hold with both hands As a welder, this also works pretty well for me. I used to get shocked constantly, until I decided to not just let gloves give me a false sense of security. Now when welding at home, I don't even change welding rods without either standing on something that is not grounded, or setting the electrode down and picking it back up with the stinger rather than holding the electrode in one hand and the stinger in the other. I also turn off breakers or unplug lamps before changing lightbulbs if it requires removing a physically broken bulb. I have been shocked countless times, most of which were inadvertent. Every time, it was avoidable. You cannot get shocked unless you allow yourself to make a circuit, plain and simple. If you can't understand that, you're in the wrong line of work.

There were a few light switches in a house I worked on that looked like that, but I didn't know that what it was called. Thanks for the information.

Thanks for covering this. We ran into this a while back and I've been struggling to figure out how to fix it.

Man, I remember as an apprentice when I first started working in residential electrical, I would always come across these Chicago and California three-way wiring methods. Very exciting💥😅 times for me back then.

So far, this is your most important video I have watched. Thank you.

Control by switching the neutral is one sure way to get somebody hurt. Never knew this was allowed and even worse that it still exists. Thanks for excellent explanation.

Thanks for posting this, I've been patiently waiting for this since you reply to me on another video. I believe Iran into this about 50 years ago at a relatives house , if I recall correctly there was power to the light fixture but it wouldn't light. I managed to change a faulty switch and got the light working but never really understood (or cared) about what was going on.

I wonder how many people have been injured, burned or killed when working on this wiring method. Thank you for the completely understandable video. I've watched your other Three-Way videos and they were also very clear and concise. I even screen-shot your diagrams for safe-keeping.

I'm rewiring all the circuits in my house and your channel has been very helpful! thanks!

Wow. This is amazing. Many years in the trade. Had no idea this method existed. You sir, have earned my subscription.

Young electrician raised on standard and dead-end methods. This just blew my mind. The ah-hah moment halfway through the video when I realized the light's polarity was going to be switched made me realize this is hick-ingenuity.

Extremely valuable information. Thank you

I have not seen a Chicago three way in years.... thanks for the Memories..

Very cool. Here in Oklahoma, many residential electricians and service electricians know of the Arkansas 3-way and the California 3-way, but this is the first I've heard of this one. - Arkansas: in old houses where the circuit hot was brought first to the fixture box in the middle of the ceiling, a 14:2 Romex cable would be taken to the first 3W switch where only the black was used for power to the switch. (The white was not used). Then between switches, again 14:2 was strung for travelers. Then a third 14:2 was run from the second 3W switch back to the light fixture as a switchleg. (Again, the white was unused.) - California: In stairwells where the circuit is closer to the upper switch and also to the fixture than any of these three are to the bottom switch, a 12:2 Romex is run to the upper switch for hot and neutral. Then a 12:3 is run from the upper switch down two the lower switch: white phased as constant hot, red and black for travelers. In the upper switch box, the circuit hot is NOT landed on the common screw of the upper switch; it is instead spliced to the hot-phased white inside the upper switch box. Finally, a 12:2 is run from the upper switch box to the fixture: white being neutral, and black being the switchleg tied the common screw.

When I first began in the early 80's I had to remove tube & wire from an old house & was amazed at the absurdity of how that place was wired- it seemed like there should have been way more fires from that type of system & yet it wasn't so bad that an impetus was generated to ban that stuff outright... CODE upgraded eventually so that you could not install that system any longer but did not require people to remove it unless/until there was an upgrade... there are still millions of homes across the USA that have that wire still functioning today... scary stuff!

Great 3way videos. Clear and simple schematics/drawings focusing on the theory of operation removing the noise of cables, boxes, and wire nuts.

Seems like Chicago was always intent on burning itself to the ground. Dang! In 50 yrs of doing electrical work I thought I had seen it all. I've even worked on a number of old homes with knob n tube wiring and never come across this one. In fact, never heard of it, but thanks for the info.

I had one of these neutral flip 3 ways in my 100 YO house, it took me a bit to figure out what they did. You see this in old houses where the light fixture was always hot and then neutral flip modified with wall switches. As soon as I removed the bulb, I figured out what they did. It was old knob & tube wire, so they grab any available neutral source and run it to the lower light switch to save wire and time. They took neutral from the outlet to the lower switch, cutting & into the hall stairwell neutral at the fixture. Then added a switch at the top of the stairs tied to the nearest neutral, then down to the lower stairs switch and flipped neutral(s) to the fixture and abandoning the fixture old neutral wire. You can call that a MN neutral flip.

I have never seen this before, and I was in the trade for 40 years. But that was in New England. Glad, this could drive a man crazy.

I have a rental property built in 1970 that had a "broken" 3-way in the kitchen. I thought the switches failed, but after replacing them I could never get both switches to work. I always used the standard method, but now I see that possibly they were wired via the Chicago method. I'm not familiar with the California method, but I'll look into that too. Thanks for the excellent tutorial.

I learned of this when I was a kid. I replaced a switch for my Mom. announced that we would do a smoke test, and smoked did come out when I turned the breaker on.

Wow! I wonder who came up with that arrangement? 😂😂 I'm glad I don't do work in Chicago! I have to say... in my 40+ years of doing electrical work (primarily industrial & commercial in SoCal/west coast & Texas) I've never come across this (fortunately, I guess!). Many years ago, I came across an old residence (that had been re-purposed to a Law office), in which I was contracted to do a lighting upgrade (the rooms all had old, 8' ballasted fluorescents)... until I discoverd that it still had knob-and-tube in the attic space - and it was still being utilized! Those conductors were all running VERY warm! That job ended up taking MUCH longer (and, costing substantially more) than what was originally quoted, as I had to [basically] rewire the entire place. Fortunately, the walls were old-school, real "bat & plaster" construction, so no fire-blocking to preventing the pulling-in of new/modern conductors. What a PIA! 😂

Learned something new today , thank you very much 👍.

Excellent explanatiin on a scary situation on an older remodel, thank you.

I figured out there was probably a way to make a 3 way with only 2 conductors but seing it explained so clearly is quite cool. Thank you.

That’s an interesting method. Thanks for showing it! 26 years in the electrical trade and I have never seen this. I have seen some knob and tube wiring that was switching the grounded side on single poles.

Retired electrician. Good explanation on the Chicago 3-Way, but you get to blow up stuff with a Farmers 3-Way.....Ran into both types on a house I bought a few years ago as well as #18 speaker wire used for wiring from the switches to the can lights in the living room.

Fascinating, thanks for the explanation.

Excellent video and explanation. Thank You

Whoever came up with that had a lot of confidence in those switches enforcing break-before-make regardless of how slowly the child moves the handle. Twist-POP.

Great explanation and diagrams. You explained so well that I saw that one coming! 😄

Great explanation, thank you! Looking forward to the explanation of the "California Three-way". Haven't heard of that one before watching your channel.

That's wild! I actually like the ingenuity of this one. I realized how it worked about 3:20 and was amazed! No place for it in modern electrical systems unfortunately.

Very informative! Not an electrician, but I’m often asked to change switches and receptacles for building maintenance. Thanks for the video.

Cant believe this was ever considered OK. First time I ran into this was in a house converted from N&T. Drove me crazy.

Not exactly what I was expecting when I saw the title "Chicago 3-way". But, logically, it makes sense. Unconventional that that light fixture will always have at least 1 hot leg I mean, it works.

Brit here - well that's crazy. Also makes an assumption that the travellers are break-before-make - or bang!

Awesome and thank you. Actually this explains why a few years ago during a gutted upgrade of the kitchen in my historic home with tube and knob, I first got zapped and then -- after fixing the mistake I must have made despite attempting to label everything -- had 240V going to a light fixture. The polarity's were flipping depending on the switch positions.

been an electrician for 25 years and this is the first ive heard of this type of 3 way. very interesting but wow that could be dangerous

Thank you, great information! I'm a home inspector, so I don't take anything apart, but it's very helpful to understand what the hell is going on behind those pesky switch plate covers. Definitely been flummoxed by this situation in the past!

Up until 15 years or so ago I was still wiring like this. Many in Cincinnati were. We just called it a 3 way

I am not an electrician but have learned over the years. I was a painter and worked on many union sites with electricians, apprentices and journeyman and would ask questions. Doing the replacing of receptacles, switches and doing new runs I found so many mistakes from so-called professionals. A handy little helper was my circuit tester. Not one was wired right! I even bought Home Depot’s “Wiring 1 2 3” and there was so many mistakes in THAT as well. Unbelievable. I should’ve been a sparky and made better money than a fkn journeyman painter. Too late now. Lol

I first encountered a setup like this in a house I had bought that was built in 1954, although it didn't use 3-way switches, it used similar methods. They had wired the outside porch light to be permanently on and use a sensor with the same wiring and circuit as the kitchen sink light and switch that controlled the kitchen light, outside light and "GFCI" plug in the same double wallplate. I wanted the light on the switch. I had everything off, yet got zapped by the neutral wires of all things. I also had the circuit breaker trip once I got everything hooked up correctly. I found out they had wired it like this where another switch on the opposite side of the kitchen, that didn't even control the light, put power through the neutral. I disconnected everything in all those circuits, used a wand toner to isolate each wire, and wired everything correctly. I still had a random hot neutral, but it wasn't in the circuit and I couldn't figure out where it went, so I capped it off, taped it off, labeled it, and stuck it back in the junction box. Poor wiring technique could have had bad consequences for someone who didn't identify it.

Doing a renovation dealing with outlets powered only while lights are switched on. This helps so much. Thanks

Excellent informative video - thank you!

Good explanation. Thanks for sharing.

I subbed for an electrician in my early twenties and we’d come across things like this on old work. My background was in solid state electronics as a kid just for a hobby but I had a good understanding of electricity, electrical circuits, and semi conductors because of this. My boss had 15 years as an electrician and 8 years as his own private company. You’d be amazed at what a lot of electricians don’t know beyond basic simple circuit breakers/switch/outlet scenarios. I remember him looking at a three phase diagram like he was reading mandarin. And another time showing him how to wire a DPDT relay to reverse polarity on a projector screen. You’d swear he thought it was witchcraft lol. Point being, just because you have a degree or certification, doesn’t mean you know what you should know, and someone without doesn’t mean they don’t know….

Electrical Contractor in Maine since 1998 and have been in the trades for over 40 years and I have seen some things....but this Chicago 3 way is new to me. Great presentation sir, thank you. I find it shocking (pun intended) that was ever Code....with no ground available it's down right reckless to have both fixture wires hot at the same time. Treat every wire like a hot when the power is on is what I tell others.....I have lost count of the energized grounds and even metal casings I have found energized over the years.

Excellent video!!!

Hours... it took me hours of monkeying to try and figure this out. I have knob and tube wiring and we were redoing the basement with a 3 way switch for the lighting. It was a good thing that i labeled each wire and the original switches. I identified neutral and hot and wired it like it should be. I then went to the other switch and what i had initially thought was hot and neutral were reversed. After hours of trying to get it wired i put the old switches back in... got the circuit to work like it used to and then replaced them with new dimable switches and wired them the same way the old switches were wired. Thankfully i wont have to worry much about the hot light when it is off because the wires are all in a junction box with a low voltage transformer which powers the lowvoltage LED puck lights.

This was done everywhere when no one wanted to break open plaster and run new wires .Not to code but works electrically !

Super clear explanation.

Great explanation, I had never heard of this.

I’m gobsmacked how crazy that is. I’ve never known anything but a true 3 way with 3/w ground Romex.

Chicago Sparky here. It's standard practice, at least with the me and the firms I've worked with, to fix these when we come across them. Another advantage of everything being in EMT.

Electricians really were haphazard decades ago. There's something probably worse at my father's place; if you turn on/off 2 switches in one room, you'll get the fixture to dim about halfway, and plugging a load into the outlet makes it dim even more. I told him to hire an electrician, oh, about 20 years ago.. to make it worse, they're the older single push-in toggle buttons

Once you wired the travelers I knew how it was going to work. I have not seen this method in practice however I have only worked on a few knob and tube houses.

Thought i was crazy . Years ago had one of these . Really thought i was crazy . Thx for the video

Why diagnosis on older buildings is difficult. I used to carry an extension cord with the end stripped and the hot wire capped. It’s a lot easier to test with a multimeter with known good reference wires. I found switched neutrals, 240v in a lighting box, and other homeowner hacks over the years.

I've never seen such a thing. Seems totally insane. The idea of a neutral being switched just can't fit in my brain. But, now you're making me wonder if my understanding of how it should work~~only switching hots~~is correct. I am definitely going to have to watch that next video.

Since the "Chicago 3-way" requires running separate conductors from the lamp holder to both switches, it must be an uncommon sight in buildings wired with sheathed 2C wiring or newer. The old wiring I've dealt with is sheathed in cardboard on top of the rubber insulation and is quite a chore to strip compared to modern sheathing where you can use the ground as a rip-cord.

I was always told this was a "California 3-way" and all the literature I read in school also refered to it as such. Also, I have heard it called a neutral switched 3-way. Good demo to explain how it actually works! Ive never thought about it ive always just fixed them or rewired them when i see them.

Great explanation!

Never assume a white wire is a neutral ever.

Thank You. Good info!😊

I learned about this the hard way after attempting to install a new light in my father's garage, built in the 1970s. I was so angry to see such a dangerous installation just to save having to put in 30 feet of 3-conductor Romex. Then I remembered getting shocked as a kid (in the same house) changing a lightbulb that was turned off.

Back in 2005 was doing custodial/ maintenance work for my church's campus. The original wiring was done back in the '40's in the old dairy barn. It was patched together with mineral insulation and K&T. But it had one of the three way switches that just about drove me crazy. Because one switch was at the back door of the shop building 150' away and the other in the barn. On and it was run underground in 3/4" steel conduit. Like to never figured that one out.

Awesome video, I believe I watched my mentor blast his way through trying to fix one of these, Awesome work 👍

I've never come across the Chicago method. However, we bought a 72 mobile home and I was replacing the porch light. Keep in mind I always kill the breaker. She also wanted to change the light switch to one of those decorator styles. When I got to the old switch someone wired it to switch the white wires instead of the black. I found it odd. I wired it correctly and all is fine now. Also, there was not any other light switch wired to white except that one. Lesson is always turn the breaker off.

You're damn right that's lethal!!! Whose GENIUS idea was this?!

Im just a diy guy but have run into this a few times helping friends debug their houses. I always assumed these live off bulbs were caused by other diy people and i would remove the second switch. Im truly surprised that professional electricians believed this was ok. You might also suggest putting a gfci outlet at the root of all two wire circuits - in case theres a partial short.