I once did a service call at a house built pre-1940.
The owner was having trouble with a cieling fixture, in the hall way, switched from both ends.
After disecting the wiring in half of this house, I finally figured out how the original electrician wired this 3-way switching.
A few of the old timers I've talked with over the years called it a Chicago Hook-up.
Anyone here know what that is?
We're talking knob and tube days ok?

10 points to the first correct answer.

How about 10 points to whoever can find the thread where we discussed this and the different variations.

-Hal

Sorry,
As I said in one of my other recent posts, I'm new here. I don't know what has been discussed in the recent past.

No problem, matter of fact it can be good to rehash this stuff every once and a while. Other new people may not have seen it either.

Thought there was an illustration in the Technical Reference Area...

-Hal

Lamplighter, welcome to the forum. Most everything under the sun has been discussed at one time or another here, but that doesn't mean we won't discuss (or argue ) it again.

Roger

https://www.electrical-contractor.net/ubb/Forum2/HTML/001385.html

Thanks guys,
I can see where the same subjects would come up every so often. The trade has a wide scope and there are almost always more than one way to get an acceptable result in the field.
Throw in the fact that there are so many members to this forum and some topics have to come up over and over.
Although, I still haven't seen anyone post the answer here. heh heh.
Just kidding.
I'll give you guys another riddle in another thread if you like.

Now I lost... Is a "Chicago" anything like a "French", or "Hollywood 3-way"??

I checked the link above and didn't see anything about the chicago hook-up however, there is a referance to a third, illegal way to make a three way system work.
I'll accept that the person who wrote about that probably knows what it is.
For those that don't here's a hint.
It is illegal and doesn't use travelers.

Check out these versions, the second one is legal, I think. These are from Coleman Electrical Graphics



or



Ronald Coleman has some very good and informative graphics on his site, check out the link below


http://home.comcast.net/~ronaldrc/wsb/html/view.cgi-home.html-.html

Roger




[This message has been edited by Roger (edited 10-18-2005).]

So, would the first method posted by Roger be legal if supplying, say, a linear halogen lamp, which has the same kind of contact on each end? It this case, there is no "shell" that has to be at neutral potential.

(Edited to fix speling.)

[This message has been edited by SolarPowered (edited 10-18-2005).]

200.11 Polarity of Connections.
No grounded conductor shall be attached to any terminal or lead so as to reverse the designated polarity.

I think what Solar is saying is there is equipment without any clearly defined polarity. A double insulated tool without a polarized plug would be another example. Anything with a transformer, ballast or switching power supply would be another example.
The real problem is the white wire, only because it is white and switched.
In the case of the power tool the disconnecting means, the plug, disconnects both wires simultanously.
At the equipment end there is no difference

It does beg the question, what if both of the switched wires to the non-polarizerd equipment were run in a color other than white?

[This message has been edited by gfretwell (edited 10-18-2005).]

See Article 404, in particular 404.2. You are simply not allowed to switch the neutral. It doesn't matter if the load is polarity sensitive or not.

Also see 300.20 (A) requiring all conductors to be grouped together in metal enclosures and raceways.

Now I suppose that if this load was fed with 2 ungrounded conductors, and was in a non-metallic wiring method, then I think that it would be allowed...

-Jon

Very nice Roger!
ten points to you.

There are many more names for that kind of setup... Hamburg three way, thunder-and-lightning three way (a reference to the fact that an arcing switch will cause a dead short in this arrangement),...
The problem is, the lights are off and you still might have a live wire up there. And it doesn't work with most modern switches. The old rotary snap switches and toggles were big and had a wide contact spacing. New decora style switches have the internal contacts much closer together, making them much more prone to arcing and shorts.
In Germany that was a way to install a grounded socket and three-way switch using only a 3 wire cable w/o ground... combined ground and neutral, hot and lamp return wire was all that was needed. In Austria it seems to have been used but I've never seen it done.