Weird (and Illegal !) 3-way Switch

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480sparky said:
Monikers include Chicago, Carter, California, Farmer, Handyman, Illinois, Power Beyond, Homeowner, DIY, Hot-wired, Husband, Three-Wire-Hot, Switchback, and my personal favorite, Who-cares?-It works,-and there's-no-inspection!.
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According to post 16 it is not a California.

Lets not also forget the Tennessee - a pull chain switched lampholder with multiple strings attached to the pull chain and routed to multiple locations:)
 
480sparky said:
I seriously doubt there's a governing body authorized for the naming conventions of these types of switch wiring.
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Indeed. These uncommon 3 way configurations, in the wild, are referred to by wildly divergent names.
 
Al, as a fisherman and hunter, I enjoy your referring to things you find in the field as "in the wild."
 
Illegal with 2011 code?

Illegal with 2011 code?

On this topic, I have a customer with a shorted [somehow, security installation or video cablers whose stuff is nearby?] traveler wire in a 3 wire w/g nm cable between a 4-way switch and the 3-way hot feed switch.

The box with the 3-way hot feed switch has a neutral present of course and I was wondering if I used the neutral in the 3 wire as a traveler between the 4-way & 3-way if that would be 2011 code ok.

Another issue is that there is a neutral available [& several other switched lights] at the load light feed end 3-way but I did not check to see if it is the same breaker/circuit. [There are four or five 4-way switches between the two 3-way switches.] Also not sure if any of the circuits are on an arc fault & would that cause issues.

So far I am thinking some sheetrock work might be order because there is a finished floor below and above the switches.
 
151118-1539 EST

Dugswork:

You can not just go grab a neutral from any old place you want.

The fundamental rule is one based on an understanding of magnetic fields:

All wires connecting to a load must be in close proximity to each other for the entire path from the energy source to the load to provide reasonable cancelation of their magnetic fields a short distance from the wires.

The two current carrying conductors in a Romex cable are about 0.2" apart. This is reasonably close together. Use two separate wires and space them 1 ft. apart and that is not reasonably close.

Around a current carrying conductor there is a circular magnetic field perpendicular to the current path with a defined direction based on the direction of current flow. Reverse the current direction and the field direction reverses. If you have two wires next to each other with exactly the same current, but in opposite directions, then a very short distance from the wires, relatively speaking, the magnetic fields nearly cancel each other. The further away the greater is the cancelation.

Get a 1500 turn air core coil wound with #33 wire about 1" in diameter. Connect this to an AC millivoltmeter. Put this sensing coil at the center of a 5 ft diameter 1 turn coil. Run 10 A at 60 Hz thru the one turn coil. My reading is about 3 millivolts. With no current flowing the residual reading is about 20 microvolts. This experiment is on my basement floor.

You should get comparable results. This coil properly orientated next to my incomming copper water line reads about 2 millivolts. Actually where I ran the 1 turn coil experiment the water line is below the floor. Another spot I read a residual of 0 to 10 microvolts. The meter resolution is 10 microvolts. About a foot from my main panel I read about 1 millivolt with the cover off.

Unbalanced fields from wires carrying the same current. or a portion thereof, can cause interference with audio equipment, heating effects, and possibly biological effects.

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al hildenbrand said:
All I did was Google "Carter 3 way" in the images section of Google and the mock up with the two physical switches was the one that caught my eye. It is of uncertain provenance and is used by an "Ask the Electrician" type of site that you can find by clicking here.

As for its age, it can't be all that old. What I liked about it is that the Hot and Neutral at each switch are not tied together, which, in my experience, is the core of what to watch out for when landing branch circuits in a new panel.
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god, i love it. we can now google sketches drawn on barn napkins.... ;-)
 
According to the ever-reliable Wikipedia, Carter 3 ways (what the OP described) havent been allowed since the 1923 NEC.

The best thing about 3 ways is they'll teach you in short order to shut off power at a breaker and not the switch. :D
 
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