"California Three way's"

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480sparky

480sparky

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Iowegia
al hildenbrand said:
Yup.

That's the one. When both threeways are down, the hot and the common-common conductors are in parallel.
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There a huge difference between the two methods.

In the first diagram (with the house and garage), there's only 3 wires making it work as needed. In order to 3-way the light, the switches are hooked up to both the grounded (neutral) and ungrounded (hot). This switches the netural, which is a violation of 404.2(A) and 404.2(B) et al. It also violates several codes in attaching the hot to the screw shell of a lampholder.

The second diagram does not switch the neutral, and still uses 4 conductors to work.
 
al hildenbrand

al hildenbrand

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Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
480sparky said:
There a huge difference between the two methods.
Click to expand...
Yes, you're right, Ken.

The first diagram you posted is, to me, a Carter, or a Chicago threeway (as the Master under whom I apprenticed called it), not a California threeway.

But I'll concede that we aren't working from a common set of definitions of these switching methods and that there are regional and even personal differences in what is "known".

In following the OP's description, it's hard to tell exactly what was there, however, the cable count (I believe what Charlie Bob means by "wires") is suspiciously high for the method to be the lampholder polarity switching method of your first diagram.

Maybe Charlie Bob can take a digital photo, or scan, of a line diagram and post it to the Forum . . . eh, nudge, nudge. ;)
 
480sparky

480sparky

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Location
Iowegia
al hildenbrand said:
.............But I'll concede that we aren't working from a common set of definitions of these switching methods and that there are regional and even personal differences in what is "known". .........
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I've heard the monikers of California, Chicago, Farmer, Power-Beyond, HomeOwner, Illinois, Carter, et al. used to describe various switching techniques.

I'll agree that the various designations are a bit of a mess.
 
cadpoint

cadpoint

Senior Member
Location
Durham, NC
Is #19 correct or not ? I mean is it Code compliant ? Did I just out right miss it? ! :confused:

I would think that if one didn't exactly ring out each set of wires that a
technician could not notice that they were involved in one of these types
of yahoo wiring technic's, as the OP stated he noted odd arrangements.

As I learned 3 way wiring, you intoduce the circuit power to the 3-ways to be in the front or behind the lamps(s).

I always have to do a sketch just the same! :rolleyes:
 
al hildenbrand

al hildenbrand

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Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
cadpoint said:
Is #19 correct or not ? I mean is it Code compliant ? Did I just out right miss it? !
Click to expand...
#19 is one of several ways of sketching the "Traveling Bus Threeway".

If one uses NM and NM boxes (or metal with slots cut - the usual eddy current mitigation procedures) then one can easily, NEC compliantly hook up #19, with the exception of running afoul of 310.4.

I personally think 310.4 is mis-applied in this case, however, the NEC language is what binds us.

#19 is an old technique. I see it most commonly, in my working range, in long hallways of ranch style dwellings wired originally in the '50s through the '70s with steel flexible conduit. A branch homerun will get to a 3-way switch at the beginning of the hallway, and the flex will snake through one or more light openings, and go to the final 3-way switch at the master bed. The homerun hot and neutral have come along with the common-common conductor and the traveler/switch leg conductor, and they will be extended to supply the outlets of the master bed. There are never more than four (4) conductors in the flex along the way down the hallway.
 
Charlie Bob

Charlie Bob

Senior Member
Location
West Tennessee
Sorry

Sorry

[QUOTE

Maybe Charlie Bob can take a digital photo, or scan, of a line diagram and post it to the Forum . . . eh, nudge, nudge. ;)[/QUOTE]

I didn't take a picture but if i was better on this computer i would draw a diagram. Sorry !!!
 
B

broadgage

Senior Member
Location
London, England
The first diagram shows a method of controlling a light from two locations (such as house and garage) whilst useing only three wires.
This is sometimes done in the UK, THOUGH PROHIBITED, it is often called "carter switching"

If one only requires to control the light from two locations then nothing is gained by carter switching, one can wire the light correctly and still only use 3 wires.

The advantage of the system, is that with carter switching, one of the 3 wires is allways hot, and one is allways neutral.
This permits of installing a receptical in the garage, wired between hot and neutral and allways live, the lamp may switched from the house and the garage, and all with only 3 wires.
The saving in material is clear, as is the violation, since both sides of the lamp can be hot, with lamp unlit.

A bit O/T, but the interior light in a London taxi is wired like that, acceptable for 12 volt vehicle wiring, but a bit perplexing when trying to fault find !
 
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