3 way switch problem

Here"s an electrical problem that"s got me confused. A few weeks ago I installed a fluorescent light in place of an incandescant light in my mom"s laundry room. The light is on a 3-way switch. With the incandescant, the 3 way switch worked fine. Now, with the fluorescent installed, you can turn the light on with either switch, but you have to use the same switch to turn it back off. If you try to use the other switch, the light will turn off for a split second and then come back on as soon as the switch travel is complete. The house was wired sometime in the 50"s or 60"s and there is only a black, white, and ground in the ceiling box. I haven"t pulled the switches out to see if they are really three way switches or if it is some type of jury rigged setup, but am headed down there tomorrow. What really has me confused is why it worked with the incandescant, but not the fluorescent.

One other thing, the kitchen has a fluorescent light and 3 way switch and it works exactly the same. It"s been that way ever since I can remember. We always knew it was wired incorrectly, but since there is no access above the ceiling to the wiring we left it alone.

I would think you have a bad switch. They are a make & break switch.

Had a problem with 3 way switch one time. Wouldn't work correctly with new replacement switch. Turned out the new switch had terminals in different positions on the switch, so when wired with wires in exactly the same positions as on old switch, it didn't work. Three way switches are a single pole double throw. This means that the switch will connect from center to either terminal, depending on toggle position.

the wireing in old houses 3way switches were done diffrent not by nema code hard to discribethey had a hot wire at both switches and also anutral then a wire from each went to the ligntat the switch the dark colored screw went to the lighr draw it on paper and followhow the circuit worked so you can understand . today's new switches wont work safly so the only way is to rewire them to today's code for safty.
old art p.s. get a electrian.

Thanks, Art. When I had a breaker box put in and new feed to the house from the old fusebox - done by pros - at nite here the 2 bulbs in the hallway glowed dimly at nite. Couldn't even tell in the daylite. Told the electricians the next day, and the older one said, oh, you have the old style 3-way, they wire differently. They reversed a wire or 2 and all was fine. I didn't want to ask too many moe details. I'll have to study out your description, I'm one of those curious fellas that likes to understand things.

And lay in a big supply of incadesents for the hallway..... The house has stood fine with this setup since 1926 so I'm not gonna get too worried about the dangers of it.

--->Paul

It is not the position of the wires on a new switch that matters versus the color of the screws the wires are attached to. You should have one dark screw and 2 lighter colored screws. Always connect the wires to the new switch by color of the screws they came off the old switch.

Dark colored screw on one switch goes to source( hot wire). Dark screw on other switch goes to load (light). Other two screws are travlers and can go on either screw. DH

Is it possible one of the switches is a dimmable three-way?

Paul,
About 30 years ago I ran into the old way of wiring 3-way switches in a house. A friend of mine changed the switch and it wouldn't work. I couldn't figure it out so I called up my uncle who was an electrician right from the beginning and he straightened me out. They are actually switching the neutral half of the time. Like old art said, draw it out with a hot and neutral on each switch and the colored screw on each switch connected to the bulb leads. With the switches in the right positions you can have 120 volts at each side of the bulb but the light will be off.

How can you switch the neutral when it goes straight from the neutral in the panel box to the neutral side of the light? Lot of old houses used a white wire for the traveler and it may get confused with the neutral. Only difference between a old three way switch and a new one is the marked screw may be in a differant location on the switch. The switch still works the same way. DH

DH,
It is in the way the wires are connected to the switch. Below is a link to a picture. This diagram also brings 120 volts and the neutral to an outlet on the far end.
Link

Around here in Ind. they were called a Chicago 3-way and at the time switching the neutral was ok. Wasn't common in the house but used a lot for out building lighting with tri-plex.

DH,
Here a copy of what someone wrote in a discussion about this. I wouldn't have known about this hook up myself if I hadn't run into it and had to figure it out to get the lights working again.

Up until somewhere in the 1920's, there was no Code requirement that the lampholder had to have the neutral on the screw shell. One will find examples of this "Carter" 3-way in electrical inspector approved installations from the first decades of the 20th Century.

Many two story homes that were wired with Knob and Tube had lighting on the main stairs that was controlled by a 3-way switching setup.

One of the 3-way switching hookups that was used was this polarity-reversing method.

One brought a hot and a neutral to each switch location and hooked them to the switch traveler terminals, and then sent one wire off to the lampholder from each switch. There was a real economy here, for the installing electrician.

I have found that many times, on little two story homes, that the hot and neutral came from different circuits, on occasion. This is a particular delight to discover on a service upgrade, when one takes one of the two circuits (both should be on the same service leg) and inadvertently puts it on the "other side" of the panel.

When the light should be OFF with both the screw shell and the center button HOT, suddenly, becomes a 240 volt bolted short circuit.

I apologise for my mistake as I have never heard of this way. All the old houses around here always had pull chain light fixtures and only one receptable per room. I am aware of knob and tube wiring as I have worked on it before. DH

Crem,That wiring was still being done into the 50s by Pros as a cost saver.One other thing that was done until the 30s??was switching(or shuting off) the neutral at the entrance boxes.

I just bought a 2 flat built in 1926. Was doing cosmetic upgrades to the upper unit. One of this was replacing the ceramic switches to current switches. I have 2 3 way switches for controlling the hall light in back and front entrances. When I changed the old ceramic 3 way switches to current 3 way switches the fuse keeps blowing. I pulled both switches and tested the 6 wires and I have 2 hot wires. I have come to understand that I may have a Chicago 3 way switch.

Do I need to get these rewired or can I get replacements switches for the ceramic to handle this wiring?

Any help would be appreciated.