3 way switching

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dicklaxt

Senior Member
Just out of curiosity,,,,,,,,is the so called California or Coast 3 way alternate scheme used much?

dick
 

kwired

Electron manager
Location
NE Nebraska
I don't recall I've ever seen it used in this area.

That's because you are not in California:happyyes:

I have only seen it used on knob and tube installations, and occasionally on a detached garage where they wanted a switch for a light on the garage at both the garage and the house. Was usually old overhead conductors between the two buildings that had been there since electricity had been discovered. Ok, since about the time when K&T installs were common.
 

480sparky

Senior Member
Location
Iowegia
They're not installed any more because they break so many NEC articles.

Calif3wayanim.gif


Today, you would need 4 conductors (plus ground) to accomplish this legally. "Back in the day", someone figured out how to do it with just 3.
 

dicklaxt

Senior Member
They're not installed any more because they break so many NEC articles.

Calif3wayanim.gif


Today, you would need 4 conductors (plus ground) to accomplish this legally. "Back in the day", someone figured out how to do it with just 3.


Thats a Chicago 3 way I believe with a little ginger bread added.The California 3 way is legal I'm thinking as it doesn't switch the neutral.

dick
 

kwired

Electron manager
Location
NE Nebraska
Thats a Chicago 3 way I believe with a little ginger bread added.The California 3 way is legal I'm thinking as it doesn't switch the neutral.

dick

so what is the "California" three way then. I have seen same circuit with both names.

I have seen other methods of sequencing switches where you could progressively turn lights on as you pass through rooms, tunnels, etc. but these all assume you will always start at one end and work your way to the other, flip a switch out of proper sequence and you possibly mess the whole thing up. A real 3-way circuit will allow you to flip any switch in any sequence and get the expected result.
 

dicklaxt

Senior Member
It took me a while to find one,,this is the California 3 way,,they said it is aka the Carter 3 way

300px-California-3-way.svg.png
 
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dicklaxt

Senior Member
I see how that works, and would comply with NEC, but what is the advantage to that?

Appears to me it requires one more conductor between switches than what most of us would run for it to work.

Correction on the Carter,,,the Carter 3 way is another name for the Chicago 3 way.

I'm not a proponent of the California 3 way, just wondered if it was used much.One advantage may be you can have switched outlets or direct wired outlets at either end giving you a bit of cost savings on wire but man how'd you like to have to trouble shoot that mess.

dick
 

kwired

Electron manager
Location
NE Nebraska
Correction on the Carter,,,the Carter 3 way is another name for the Chicago 3 way.

I'm not a proponent of the California 3 way, just wondered if it was used much.One advantage may be you can have switched outlets or direct wired outlets at either end giving you a bit of cost savings on wire but man how'd you like to have to trouble shoot that mess.

dick

Doing it the "conventional way" still allows for feeding other loads beyond the switched load using the same amount of wire. I still see no advantage.
 

dicklaxt

Senior Member
You don't have a constant hot at the far end with the conventional method as I see it,do you?

The flow of devices in schematic being from left to right.......... bkr,sw, sw & light.

dick
 

kwired

Electron manager
Location
NE Nebraska
You don't have a constant hot at the far end with the conventional method as I see it,do you?

The flow of devices in schematic being from left to right.......... bkr,sw, sw & light.

dick


No, you don't have a constant hot, at the switched load in that schematic.

You do have one at the last switch if you wanted to continue from there with another load that is always hot.

If you connect the three ways via the "conventional" method you still can have a constant hot at the last switch if you run the same number of wires between them. If you don't need a constant hot at this point then you can wire this the conventional way using one less conductor. That is why I ask what the advantage is.
 
On the East Coast , I learn it as "hot traveler's" , you only see it in really old house's 30's and very infrequently (maybe 3 times in my 30+ yrs (working NY and NC)) because of this I was taught it must of been outlawed in the 30's.
 

broadgage

Senior Member
Location
London, England
It has been outlawed here for decades, but I still find examples !
Seems especialy popular for staircase lighting in old offices, the advantage being that an outlet may be provided next to each switch.
We dont normally put outlets and lights on the same circuit in the UK, not prohibited, but just not the done thing, except in office stairways.
In the UK, we call it "American switching"

Useless trivia--------the internal lights in some London Taxis are wired thus, works fine and seems safe enough on only 12 volts, but most perplexing if the cab driver replaces the supplied incandescent bulb with an LED one which works only with the CORECT DC POLARITY which is only achieved half the time.
 

kwired

Electron manager
Location
NE Nebraska
In the UK, we call it "American switching"

That's OK. I'm sure I have heard worse titles over the years for European equipment or the way it was designed over the years:)

At very least some cussing about needing to use metric wrenches or sockets to work on the equipment.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Just out of curiosity,,,,,,,,is the so called California or Coast 3 way alternate scheme used much?

dick

It took me a while to find one,,this is the California 3 way,,they said it is aka the Carter 3 way

attachment.php
The problem with the so-called California threeway shown in this diagram occurs when one uses the lower traveler (the always hot traveler) to supply downstream load.

When both switches are off and in the "down" position, any load downstream of the right hand threeway will have its load current split between the lower traveler and the common to common conductor. This is a parallel installation and the conductors are smaller than the 1/0 allowed in 310.10(H).

In the metropolitan area that I work in, I find this switching setup in dwellings built from WWII into the '70s, especially if they have long hallways with hallway lights at multiple locations. The wiring method is flexible metal conduit. A lot of installers used the California threeway to minimize the number of wires pulled and to shorten the runs of FMC.
 
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