# Chicago/Carter 3 way??



## chicken steve

Welcome to ET Trav, you need to get your head around this>>>>









~CS~


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## Travvy

That diagram makes sense to me. But why won?t the breaker hold with the new switches? As far as we know everything worked before replacing them. Is there something about new switches that doesn?t allow this method to work or is ther another issue?


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## hardworkingstiff

Travvy said:


> That diagram makes sense to me. But why won?t the breaker hold with the new switches? As far as we know everything worked before replacing them. Is there something about new switches that doesn?t allow this method to work or is ther another issue?


Please don't take offense, but my guess would be that you don't correctly remember what you looked at. 

W/out a rewire, you need to drop the fixtures so you can see what wires are in there, ring out all the wires in the switch boxes so you know where they all are going/coming from, then come up with a reconnect plan.

Edit: Write it all down, don't try to remember what goes where.


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## EC2253

If this is a hot to hot switch wired with knob and tube then there is only 2 wires in the light box. If you changed out the service then you may have different legs(potential voltages) at the switch boxes witch would send 240v to the light box.


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## telsa

OP...

Carter switching switches the Hot at one three-way switch...

And switches the Neutral at the other three-way switch.

Switching the Hot does not create a hazard at the j-box feeding the lamp(s).

It's switching the Neutral that causes the lamp to go out -- because it's being double fed with 120VAC.

This is beautifully laid out on page 57 of David Shapiro's "Old Electrical Wiring."

ISBN 0-07-057879-6

Shapiro dedicates a chapter to this scheme.


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## MechanicalDVR

Not to sound like a prick but there is a reason one needs several years of experience before they should be out working on circuitry independently on their own.

Chances are you created a short by a wire in the wrong position.


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## telsa

Bingo.

He's so green that he didn't instantly pick up on that.


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## frenchelectrican

EC2253 said:


> If this is a hot to hot switch wired with knob and tube then there is only 2 wires in the light box. If you changed out the service then you may have different legs(potential voltages) at the switch boxes witch would send 240v to the light box.


That is the main reason why I mark the conductors in phase tape so I know which way it will land when I install the new service box.

It did happend to me before once so after that I got wise with it.


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## EC2253

MechanicalDVR said:


> Not to sound like a prick but there is a reason one needs several years of experience before they should be out working on circuitry independently on their own.
> 
> Chances are you created a short by a wire in the wrong position.


Yeah this is one of those if you can keep thinking about it soon you will say
"oh i get it now".


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## MechanicalDVR

EC2253 said:


> Yeah this is one of those if you can keep thinking about it soon you will say
> "oh i get it now".


I've seen some where all the wire jackets were the exact same color and if you don't mark them you'd have a rough time getting them all back in the correct locations if you didn't have a photographic memory.

It can get busy in a two gang box when you have a couple extra pair taking power off the three-way set up.

I just don't think this is a spot for a newer apprentice to cut his j-man teeth.

While I know many apprentices take on side work the day after they get hired I also know of many that had to beg their j-man the first week to come look at a job they screwed up.

That smart phone/google/youtube really isn't a substitute for some actual field experience.

I know that goes against the typical millennial mindset feeling they can do everything and need j-man wages right out of the gate.


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## chicken steve

hardworkingstiff said:


> Edit: Write it all down, don't try to remember what goes where.


^^^^*THIS*^^^^^ is what we all did when we were lost pups...:thumbup:~CS~:thumbup:


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## splatz

Long ago I learned to put tape markers on everything before I took anything apart. 

Later I learned to put tape markers on everything AND take a couple pictures with the phone before I take anything apart. 

Build a drawing as you go.


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## chicken steve

I _fergit_ what year it was they had us all draw 3 ways in class...then told us to find other '_ways_'....:blink:~CS~


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## lighterup

I would do a drawing...an escape route out the back door leading to
my 2016 Ford Transit-mobile.

I'd be .."re-wire the whole house or thanx but no thanx."
:scooter::scooter::scooter::scooter:


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## frenchelectrican

lighterup said:


> I would do a drawing...an escape route out the back door leading to
> my 2016 Ford Transit-mobile.<<<<
> 
> I'd be .."re-wire the whole house or thanx but no thanx."
> :scooter::scooter::scooter::scooter:


Ford Transit miluwakee battery powered vehicle ?


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## frenchelectrican

chicken steve said:


> I _fergit_ what year it was they had us all draw 3 ways in class...then told us to find other '_ways_'....:blink:~CS~


I did not do that in class but learn it on the site rather harsh way but once you know it will not escape your mind.,,


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## Travvy

Thanks for all the responses. I take no offense whatsoever when people point out my mistakes. I wish I would have never touched it, but I?m down the rabbit hole now. 

My boss wants to be as fair as possible with the customer regarding pricing. He doesn?t want to simply put it back the way it was because it?s dangerous. They thought they were going to be paying for an hour of labor and now they are looking at a day?s worth of work to make it safe and legal.


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## active1

I seen the diagram in textbooks but never remember seeing around Chicagoland.
I would guess as early as the 1920's everything was in black RMC.
Sometimes converted gas pipes from gas lighting. 
Later everything was EMT when that came out.
Depending on how close you were to the city and what year varied how stringent the codes were. Seen number of old stick homes built with RMC.
When you run conduit the Carter 3 way most of the time would be pointless as you need to connect the next box with a conduit. 

IDK about the late 1800's to early 1900's. When we got to that old we just ripped it out and never took time to figure what was going on. 

I seen switched neutrals instead of hots in some old places.
But that along with the Carter 3 way didn't meet the Chicago code.
At least not Chicago Electrical Code 1938.
1204. a. (page 210) No switch shall be installed on the grounded conductor unless the switch simultaneously disconnects the ungrounded conductor... 

Another old one was green switch legs or hots. IDK what year green was designated the EG or how long after it took electricians to quit using it for a switch leg or hot. I would guess 1950's.

Mercury switches are another fun one for people not used to it.


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## frenchelectrican

active1 said:


> I seen the diagram in textbooks but never remember seeing around Chicagoland.
> I would guess as early as the 1920's everything was in black RMC.
> Sometimes converted gas pipes from gas lighting.
> Later everything was EMT when that came out.
> Depending on how close you were to the city and what year varied how stringent the codes were. Seen number of old stick homes built with RMC.
> When you run conduit the Carter 3 way most of the time would be pointless as you need to connect the next box with a conduit.
> 
> IDK about the late 1800's to early 1900's. When we got to that old we just ripped it out and never took time to figure what was going on.
> 
> I seen switched neutrals instead of hots in some old places.
> But that along with the Carter 3 way didn't meet the Chicago code.
> At least not Chicago Electrical Code 1938.
> 1204. a. (page 210) No switch shall be installed on the grounded conductor unless the switch simultaneously disconnects the ungrounded conductor...
> 
> Another old one was green switch legs or hots. IDK what year green was designated the EG or how long after it took electricians to quit using it for a switch leg or hot. I would guess 1950's.
> 
> Mercury switches are another fun one for people not used to it.


Green switch legs .,, Jezz that did bring up memories on that when I was living in France and yuh in very old french codes the green was used for phase conductor !!! but it no longer legit they stop useing that in late 50 maybe early 60 era ., 

Mercury switches .,, now that is the other item .,, they are very picky on how to keep it level to work properly .,, oh yuh ., any hard short circuit will just blow them out pretty good. alot of peoples learn that in hard way due some used the mercury switches to control common run of mill small single phase motor(s).

Anyone try to install mercury switch upside down will learn this in hard way.,


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## active1

I just remember the mercury switches when removed from the switch box.
If it was bumped or fell to a bit off the normal position the switch could make contact and energize the circuit. Bad for using as a disconnect for changing out fixtures.

I still got 1 new in the box.
GE Super Switch, lighted
50 (fifty) year guarantee not to fail in normal residential use. 

Here is a video of the same:


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## telsa

active1 said:


> I just remember the mercury switches when removed from the switch box.
> If it was bumped or fell to a bit off the normal position the switch could make contact and energize the circuit. Bad for using as a disconnect for changing out fixtures.
> 
> I still got 1 new in the box.
> GE Super Switch, lighted
> 50 (fifty) year guarantee not to fail in normal residential use.
> 
> Here is a video of the same:
> https://www.youtube.com/watch?v=X9t5XP6tfvc



My Uncle paid the premium demanded -- fifty-years ago -- to have mercury switches instead of the cheesy stuff.

They are still working like new... 53 years later.


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## sparkiez

I'll be darned. I have pulled probably a couple dozen of old GE switches that looked a lot like that out. I never bothered seeing if they were mercury switches though. Looks like I shouldn't have just thrown them in the trash. I honestly didn't even know they ever bothered making single pole mercury switches.


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## frenchelectrican

sparkiez said:


> I'll be darned. I have pulled probably a couple dozen of old GE switches that looked a lot like that out. I never bothered seeing if they were mercury switches though. Looks like I shouldn't have just thrown them in the trash. I honestly didn't even know they ever bothered making single pole mercury switches.


I did remember they came in both single pole and three way verison.

but the thing I hate about the three way mercury switch is ya cant run it in Hortzonal postion at all ( same way with single pole mercury switches )


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## active1

You know there was one guy back in the day that held the switch in his mouth while prepping the wires. There is always one person that uses there mouth as a 3rd hand. You know the guy that will chew on their Klein screwdriver while working. Or will chew on a roll of electrical tape.

Those switches have a feel more like a dimmer slide when you turn them on vs a snap or click. Or like a worn out snap switch. No noise. They are solid. Just don't like the feel of the action myself.


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## fdew

I have a gas fireplace with a millivolt control. I put a normal PSST light switch on the opposite wall and it lasted almost a season. It just wasn't made for a requirement of almost perfect contact / no resistance. I searched E-bay and found a NOS mercury switch. It has been in there 10 years now. Works every time.


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## PokeySmokey

Both Carter and Chicago 3 way wiring methods are unsafe and illegal in Canada.

The key to ensuring neither switch creates a short circuit in either position is you line and neutral MUST be connected to the traveler terminals. If either a Line or Neutral is connected to the common, the 3 way switch will short circuit in one position.

The commons on both 3 way switches are connected to the light fixture.

If you mark the terminals feeding the light fixture on the Carter 3 way diagram near the beginning of this discussion you will see the other 2 terminals which are normally for the travelers have the Line and Neutral connected to them.

When I was a first year apprentice my J man gave me a task to draw a wiring diagram to supply power to a receptacle near the second 3 way switch using only 3 wires between the 2 3 way switches. The line and neutral fed into the first 3 way switch box. Took me a while but I succeeded. Then he said NEVER use this wiring method and I never have. Now I know the name of that wiring method: Chicago 3 way circuit.


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## goodtimesgladly

Travvy said:


> Thanks for all the responses. I take no offense whatsoever when people point out my mistakes. I wish I would have never touched it, but I?m down the rabbit hole now.
> 
> My boss wants to be as fair as possible with the customer regarding pricing. He doesn?t want to simply put it back the way it was because it?s dangerous. They thought they were going to be paying for an hour of labor and now they are looking at a day?s worth of work to make it safe and legal.


I know I have used this saying before but I wish I had a nickel for every time a homeowner or landlord called me for a three way problem. Ninety nine percent of the time a diy idiot or homeowner or a friend said "I can replace your switches for you". They do not know the difference from a standard and a three way. A guy did this to my Mother. She would have asked me but I have a couple of other businesses keep me busy so she did not want to bother me and I hate residential work. I do not know if I were more mad at my mother for letting this F*ck head do it or at the F*ck head that did it.
F*cking nightmare. It took me 4 hours Ill bet to straighten it out and it was only one light. The switches were strange because they had lights that would light up when off and go off when on. There were more wire in the boxes then were needed and there had to be a couple of rolls of tape on everything and I think there were a couple unused wires when I finished. I continuity test the wires and marked the wires and I finally got it to work but that is the last three way I will do unless it is mine and I start the job.


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## fdew

If I was in this mess (I have been in similar ones) I would label every wire with a number, Then remove the wires from the switches and light fixture, then find the hot(s) and neutrals and write down what label they have. Then get a telephone toner and tracer connect one lead of the toner to ground and the other lead to a wire. take the toner and find the other end. Write it down. Repeat until all wires are identified. Make a drawing with the two switch boxes and the fixture and all the wires. 

Once you have the drawing you should be able to figure out how to wire it. 

A lot of work but faster then guessing. I bet you would be done in half a day.

Frank


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## telsa

Some troubleshooting tips for the Industrial & Commercial electricians trying to save momma.

1) Houses -- usually -- are wired with CABLE. 

If it ever was correctly wired in the first place, the heart of the matter is to discover the travellers -- and the boxes they connect.

The 3-ways are usually pretty obvious: they are at the top and bottoms of stairways -- or at the entrances to rooms with multiple entries.

2) The power to the first, line-side, 3-way figures to be in 14-2 Romex.

2a) The travellers leave via 14-3 Romex. ( Not true for Carter 3-ways -- which is a BIG 'tell.')

3) If a 4-way is in the chain, it'll be mighty obvious: 14-3 coming in, going out and 4 connections to the $.)

4) The final 3-way should send the switch leg out as 14-2. 

4a) One determines line and load via capping off both hots (one at each j-box ) and powering up the breaker -- then using an influence tester// DMM// Wiggy.

The switch leg can hit the light string at any point -- as they are all wired in parallel.

&&&

A Carter 3-way is given away by having only two quasi-travellers. That is, 14-2 joins the switches.

Then it's essential to know which 3-way is Line, which is Load side.

1) The Load side 3-way is breaking // switching the Neutral.

2) The Line side 3-way is breaking // switching the Hot.

The quasi-travellers are alternating the role of each conductor from Hot to Neutral. 

Real travellers alternate the role of each conductor from Hot to Cold // dead.

&&&

Where circuits are piped ( Chicago, Palo Alto ) things can get more complicated because extra j-boxes may be involved -- and all of the conductors could be found emanating from one pipe.

But, a bit of tugging on conductors can resolve matters pretty quickly. And there are other tricks.

Four-hours to dope out a corn-fused 3-way ? 

Oh, my.


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## telsa

K & T is another battle -- for another time.

In such systems, switching the neutral was quite common, as was room entry via a top-box in the center of the room from which a central light fixture was mounted directly below.

Switch-legs ran off to the doors, in such a scheme.

You'd also run across all black conductors -- nothing is red, nor white, nor green.

Lot's of fun, then.

( You'd usually see (black) grounding conductors only in ancient piped systems... and even then it'd be uncommon. ( too expensive, the pipe would have to do ))


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## fdew

telsa said:


> Four-hours to dope out a corn-fused 3-way ?
> 
> Oh, my.


I agree, but the OP wrote "They thought they were going to be paying for an hour of labor and now they are looking at a day?s worth of work to make it safe and legal."

I spent 10 years trouble shooting commercial fire alarm systems and I agree with and have used all the tricks about comes in as three, In the top or in the bottom of the box. They are all good clues and have saved me many hours, but when all else has failed as it seems to have here then I would ring out the individual conductors.


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## active1

"Now I know the name of that wiring method: Chicago 3 way circuit"
It's been against Chicago code for at least 79 years.
In Chicago we called them Cargary 3 ways.


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## millelec

Some good tips here. I work in a power house for my day job, so resi is not my usual bag. am licensed and insured, though, and every once in a while will take a job if friends need help. The most abused item I run into is 3 way switches, especially in older houses.


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## Wiredindallas

I call that type of 3 way a California 3 way. Each switch takes either a neutral or a hot to each side of the light. When you get a hot from one switch and a neutral from the other switch, the light works. When you get 2 hots or 2 neutrals, it does not work.


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## stiffneck

Fascinating, years ago, when at a friends parents house, (built 1931) north of East St. Louis, IL. I came across a similar scenario. At the back door, of kitchen to outside and another door to down stairs where 3 switches. 1 for kitchen, outside and stairs. The stairs had additional switch at the bottom. Depending on which switch was on (kitchen or outside) the stair light would burn "extra bright" and "didn't last long". I asked how long it had been this way? They did not know, because it had been mom's uncle's house before. I rewired the stair light completely with two new 3-ways, wire, separating it from the others. The kitchen had a total of 3 different switch locations. The house was K&T, but had a newer service. The year was maybe 1990.


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## splatz

The California is different - it's still legal and occasionally useful. One extra wire and you have a switched hot on both sides. 



Wiredindallas said:


> I call that type of 3 way a California 3 way.


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## Helmut

splatz said:


> The California is different - it's still legal and occasionally useful. One extra wire and you have a switched hot on both sides.


What good what that do?


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## splatz

Helmut said:


> What good what that do?


If you want loads on both sides controlled by the three way switches, the California does it with one fewer wires.


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## Grounded-B

Travvy said:


> When I first looked at it I knew it looked weird but I figured that if I installed the new switches the exact same way that everything would work. But the breaker keeps tripping.
> 
> I?m an apprentice so I am having trouble wrapping my head around this. My journeyman has never seen this either so we are going to rewire to bring it up to code. I?m just very curious about what I?m seeing here.


 
You are seeing the "Coast" method of wiring three way switches. The problem is, that newer three ways short the two traveler terminals for a brief second, before switching. This causes a dead short between Hot & Neutral.


You had it wired correctly.


Steve


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## Grounded-B

Travvy said:


> That diagram makes sense to me. But why won?t the breaker hold with the new switches? As far as we know everything worked before replacing them. Is there something about new switches that doesn?t allow this method to work or is ther another issue?



The problem is, that newer three ways short the two traveler terminals for a brief second, before switching. This causes a dead short between Hot & Neutral.


You had it wired correctly.


Steve


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## B-Nabs

splatz said:


> The California is different - it's still legal and occasionally useful. One extra wire and you have a switched hot on both sides.


The story I heard about California 3-ways was about how it got its name:

Apparently at one time you were allowed 4 #14s in a 1/2" pipe in California, and so the method you posted was used to feed a constant hot, 3-way switched hot, and neutral to an outbuilding underground using only 4 conductors, so you didn't have to run a bigger pipe (idea being to have a light at the main building and outbuilding on the same switch, as well as a receptacle at either end). 

I have no idea of the veracity of this story, but it's what I heard somewhere. 

Sent from my SM-G920W8 using Tapatalk


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## Grounded-B

B-Nabs said:


> The story I heard about California 3-ways was about how it got its name:
> 
> Apparently at one time you were allowed 4 #14s in a 1/2" pipe in California, and so the method you posted was used to feed a constant hot, 3-way switched hot, and neutral to an outbuilding underground using only 4 conductors, so you didn't have to run a bigger pipe (idea being to have a light at the main building and outbuilding on the same switch, as well as a receptacle at either end).



Yes, That is what I have heard also.


Back when you were pulling RHW wire through rigid. (4) #14's RHW was the max


RHW is much larger diameter than THHN !!


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## jelhill

hardworkingstiff said:


> Please don't take offense, but my guess would be that you don't correctly remember what you looked at.
> 
> W/out a rewire, you need to drop the fixtures so you can see what wires are in there,* ring out all the wires in the switch boxes* so you know where they all are going/coming from, then come up with a reconnect plan.
> 
> Edit: Write it all down, don't try to remember what goes where.



Right on.... I was getting ready to tell him to ring it out.... but do you think he knows what that means? :smile:


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