I know a lot of you guys/gals have probably ran into this set-up before but last week was the first time for me. Old 2 story house with a light in the downstairs dining room controlled by 2 3-way switches. Switch(es) have gone bad and the light can't be turned on. I remove a switch and find there are no markings to identify any terminal as common. Can't ring out a switch because they show no continuity between any terminals in any switch position. Each switch box contains 3 cloth covered wires- red, white and black. The white wire is a grounded conductor, the black is hot and the red rings out as a traveler between the boxes. I figure the only way to hook this up to 2 new 3-way switches is to connect the "traveler" to the common terminals and the hot/neutral wires matched up to the traveler terminals. It worked but I am at a loss as to why anyone would choose such a complicated 3-way set-up. I figure that in one switch position the neutral is broken to the light and in the other position the hot is broken. Can anybody offer any insight to this wiring method?
I'm not quite following your language, Fred, but Jon is right, if you are switching the neutral, it's a dangerous situation.
I have run into this situation many times with old varnished-cambic wires. I'll try to explain how I repair it.
I remove both switches and do continuity tests (power off)to find the two travellers. You can't relie on the wires color coding because often the white wire is really a switched power wire. Often you can identify the power going into one of the switches if it ties in with other power wires. The switched power wire to the light can easily also be found with a continuity tester (power off, light removed). With proper safety gear you can also energize the circuit and find the power wire with a volt-meter. The travellers and light-power wire will be de-energized since the switches are removed. Once you've found the travellers and commons (incoming power on one switch, and out-going light wire on the other), the reassembly is simple.
I usually tape all the wires as this type of insulation is inferior, especially at the lights, where the heat of the lamp makes the insulation brittle.
Dave, Re-read my post. There is only one traveler and hot and neutral on both ends. You cannot make the light come on from jumpering wires on one end. It's not at all wired like any acceptable 3-way configurations. I am aware that it is wrong now as it has been for the last 70 years. It can't be fixed without ripping out a 14' plaster and lath ceiling and part of a wall. I was just wondering if anyone else runs into this and if it was common practice in years gone by. They used to fuse the neutral in houses of this era. Was that ever considered proper?
It's important to remember that this was a legal circuit at the beginning of the 1900s. Polarization of the lampholder happened about 15 - 20 years into the century. Putting the switch in the neutral was stopped about the same time.
A lot of dwellings were built with code compliant original installations that get grandfathered in now, even though the circuit is recognized as hazardous now.
We call this a hot 3 way here in the northeast. Most common place to encounter this set up is at older dairy farms. This is so the farmer can turn on flood lights at his house and barn at the same time. A sw is at the house,and one sw at the barn.
If this diagram in txsparky's post is correctly indicating your situation, all I could suggest is to install a wall-sconce above either or both switches (fish a short wire from the switch to the re-work box above).