Odd 3-way usage

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greeny

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I recently did a small side-job consisting of replacing some old cloth insulated wire for a light fixture when I found the oddest connections to some 3-way switches. There were (2) 3-way switches operating a light fixture. Both 3 way switches had a hot and neutral terminated to the traveler connections. The point from both of them was connected to the light fixture. When the light is off, the conductors at the luminaire are either both hot, or both neutral. When the light is on, one conductor is hot and the other is neutral. At times, the screw shell is hot, even when the luminaire is "off". Has anyone ever seen these connections before. I know it's not legal, but was it ever? The wiring system was probably installed in the mid 50's.
 
greeny said:
I recently did a small side-job consisting of replacing some old cloth insulated wire for a light fixture when I found the oddest connections to some 3-way switches. There were (2) 3-way switches operating a light fixture. Both 3 way switches had a hot and neutral terminated to the traveler connections. The point from both of them was connected to the light fixture. When the light is off, the conductors at the luminaire are either both hot, or both neutral. When the light is on, one conductor is hot and the other is neutral. At times, the screw shell is hot, even when the luminaire is "off". Has anyone ever seen these connections before. I know it's not legal, but was it ever? The wiring system was probably installed in the mid 50's.
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Was this a Knob & Tube insatll or conduit, The reason I ask is I have come across alot of K&T jobs where the electrician that installed it had no consern about color of the wire ,wht was hot ,blk was neutral, you name it it seems bake then wire was wire regardless of what color it is. A traveler can seem to be a neutral when it isn't.
 
Yes

Yes

I have seen that before. You described the circuit perfectly, and that's exactly how it works. Like many things, it was probably legal when it was done, but obviously would not be today, since the neutral is broken and does not always connect to the screw shell.

Depending on why you're asking, if this fixture and its wiring are not being touched, and are located away from grounded surfaces, such as those found in bathrooms and kitchens, I'd leave it alone; if you're working on this wiring, you should make it compliant.

By the way, an extension cord plugged into a properly-wired receptacle along with a (preferably solenoid-type) voltage tester make excellent tools for identifying hots and neutrals during tracing and trouble-shooting. You have a hot, a neutral, and a ground reference.
 
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It was not knob and tube. Just old cloth insulated cable. I opened every device and outlet box in that circuit and followed the home run into the fuse box. When I say neutral, I'm not calling it a neutral because it's white. I call it a neutral because I spent a lot of time following every conductor of this circuit and am sure that it's a neutral. In fact, the wrong color was often used. The 2 wires that terminated to the luminaire were in fact both red(one from each 3-way).
 
I think that the 1923 code made that method a violation, but it was used in many areas long after that.
Don
 
Thanks for the input guys. Larry, I was replacing the wiring in a water-damaged ceiling. The homeowner wanted the wiring replaced while the ceiling was removed. I replaced both cables from the light fixture to the 3-ways and wired them correctly. Unfortunately, one of the 3-ways shared a device box with another 3-way controlling a luminaire in another room. It was wired that funky way too, but it couldn't be fixed without pulling the ceiling down in that room too. I left it, informed the h/o, and told her I would find out more about the situation.
 
This sounds alot like what a thread was not to long ago.I think it was called a chicago 3 way ????In which a 3 wire fed an out building with a 3 way that had a hot and a neutral for receptacles.From what I remember the lamp holder would flip from neutral to hot on the shell while the receptacle was still hot all the time.Anyone remember this thread ?????
 
Greeny,

That's how they use to wire all knob and tube 3way switches, probally the

same guys used NM in the same way!!

I still remember the first time I came across it, and had no clue,I was at

that job for a long time.
 
greeny said:
The wiring system was probably installed in the mid 50's.
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Greeny,

That's one of the youngest installations of this switching setup I've heard of. I'll bet there's an interesting story associated with who ever did the work. . . as Larry and Don note, this is an old technique that the NEC outlawed for new installations early last century.

The most common residential installation of a 3way, back in the first quarter of the 1900s, was in the stairwell of two story dwellings. But many dwellings didn't have more than a 30 Amp service, and many of those were only 120 Volt. There'd be two circuits for the entire dwelling, one for the kitchen outlet and one for the lighting throughout the house. Maybe there'd be one outlet set in the living room for the radio. (I've found this original circuiting in a lot of the dwellings I've worked on, over my career.)

The original lampholder-polarity-switching-3way would be part of that first single lighting circuit.

Over the decades, as new receptacles and luminaires are added to that first circuit, like as not, the circuit would get split. Many times, the 3way would end up between the upstairs and downstairs circuit. Then, no matter what position the 3way switches are in, something messy is happening.
  1. Hot to hot connection
  2. Neutral to neutral connection
  3. Load current from one circuit, returned on the other circuit.
I can still hear my old master teaching me to pay attention to how I feed the original circuits in the new upgrade panel. I can hear him telling me to be sure that all the old circuits are on the same bus bar. . . He only had to deal with what he knew was a problem on a service upgrade. . .If he put the old (original) circuits on the same bus, he knew he'd never get a call back, and he wouldn't have to investigate the wiring he was re-energizing.
 
What you have encountered there is an installation that is refered to as "the Carter Wiring Method". It may also be known by other names, but that is the one that I was told about. It is one of the earliest forms of multiple location switching that I have ever come across. I have run into these installations only twice in 20 years. It takes you a few minutes to figure out what it is you are looking at when you run across this. It's amazing the things they used to do years ago.
 
al hildenbrand said:
. . . many dwellings didn't have more than a 30 Amp service, and many of those were only 120 Volt.
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Let's not forget that both conductors were fused, too!

I can still hear my old master teaching me to pay attention to how I feed the original circuits in the new upgrade panel. I can hear him telling me to be sure that all the old circuits are on the same bus bar. . . He only had to deal with what he knew was a problem on a service upgrade. . .If he put the old (original) circuits on the same bus, he knew he'd never get a call back, and he wouldn't have to investigate the wiring he was re-energizing.
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Wow, sage advice. I guess I've been lucky to have not had interconnected circuits on the K&T work I've done.

As Spock-with-a-beard said, "Captain Kirk, I shall consider it!"
vulcan.gif


In the future, I will, at the very least, use my extension-cord-and-wiggy method for checking for grounded and interconnected conductors.

Here, in the Capital of the Confederacy, I have seen pre-civil war houses that have had at least three electricial installations over the years: single 30a 120v service; 60a 240v 2-pullout/4-plug fuse; 100a 240v 6-pullout/12-plug fuse.

Re-feeding old wiring can be a real experience. I will say that the guys who lifted floor-boards to run K&T, cut box holes into baseboards and plaster walls, and pried off baseboards to drill down into interior walls, were real artists.

I remember reading old books in elementary school about wiring existing houses. I've never forgotten most of the images and methods described, and still to this day use most of the same methods in old work.
 
allenwayne said:
This sounds alot like what a thread was not to long ago.I think it was called a chicago 3 way ????In which a 3 wire fed an out building with a 3 way that had a hot and a neutral for receptacles.From what I remember the lamp holder would flip from neutral to hot on the shell while the receptacle was still hot all the time.Anyone remember this thread ?????
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Allen, was that a "California 3 way" ? Or the old "Carter System"?
 
stickboy1375 said:
The thing I wanna know is how they get the outlet installed since I can never remove them... :) (wire is always 2 inches long... )
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That's an easy one:

Since they used sectional boxes with removable side plates, they simply removed the sides, installed the receptacle, attached the wires, reinstalled the sides, and then installed the boxes in the baseboard.

Maybe not, but it sure works when you need to replace a receptacle. The other option would be to remove the cable, strip it back a couple of inches, and reinstall it.
 
allenwayne said:
This sounds alot like what a thread was not to long ago. I think it was called a chicago 3 way ????
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That's how I remember it named too, Allen.

For those interested, Click here for a thread of a California threeway.

Click here for a thread of a Chicago Threeway.

Click here for some of the goofiest switching methods known, including the Travelling Bus. It's the coolest brain teaser you could ask for. :)
 
georgestolz said:
Click here for some of the goofiest switching methods known, including the Travelling Bus. It's the coolest brain teaser you could ask for. :)
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Figuring that if George thought it was a cool brain teaser, I needed to check it out, I did --

img33.jpg


Very clever, I must say.
 
Aint this also known as a "Hollywood 3-way"... (One more alias)

I love when someone tries to put a dimmer on one.... A HO stuck 4 in before calling....

You also have to realize nuetrals were fused when they installed these... If the original panel is still there, its a good tell-tale for pre-1906 around here. (Pre-earthquake)
 
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