Hello I am having trouble fixing some wiring in my house. I have an older home that has wiring from around 1945. It's that old two prong ungrounded stuff that crumbles when you try to strip it. Anyway, almost all the outlets in my house are ungrounded, and so are the light switches. I have had trouble with one particular outlet, and I have isolated it to a double lightswitch and it is pigtailed to an adtional set of 4 lights upstairs. Now the 4 lights upstairs work just fine. However this one light will switch on at 123 volts and then it will switch off to 75 volts which is obviously not off. I just replaced the switches so that is not the problem, however I am not sure if I am wiring it wrong or what. I had to take the circuit box apart because the previous electrician took a neutral from a different circuit breaker and it caused all sorts of trouble. But when I originally bought this house last year this light worked. Please help I am not an expert but I can usually do pretty well. No matter what I try or how I wire it there is no way to get this light 100% working correctly.

With a home as old as yours and wiring that is failing, connections that are corroded, and parts that may be worn, it is difficult to point you in any specifc direction.

We would need photos of what you have, and wiring diagrams to understand how these devices are connected.

It appears that you have at least two circuits sharing a common neutral, or you have a backfeed through a 240 volt applaiance. Start at the breaker box and turn off breakers until you have no power at that switch. Then you can straighten out the wiring after you have isolated the circuits. When the switch is off, the lights are off... correct?

OK, well to give a little more history on this problem. The house is actually a duplex and I discovered that they had borrowed a neutral from an upstairs circuit(different breaker box completely) and this caused problems when I tried to install some grounded outlets. I believe this was done because there was a problem neutral, however I do not know where it is.

I do not really know the wiring exactly I just have theorys. I have 3 pairs of wires coming into an outlet box. Set 1 apears to go upstairs so I tied that one off back to an exclusive upstairs circuit and it works fine.
Set 2 apears to be two hots coming from the three-way switch in the wall. I connected these to another set of wires that goes to a second switch and then the single wire(hot) comes back to the light bulb. I have checked wiring diagrams online on how 3 way switches are wired so this appears to be correct.
Set 3 gets confusing it apears to be one hot and one neutral that goes to the wall switch. It seems to then go on and go to another 4 lights on the main floor 3 of them are on the same switch panel and they work fine no matter which leg I make hot and which one I make neutral. I currently have the hot lead going to the leg that is connected to the dark screw on the switch(as it should be) and that seems to give me the duel voltage problem. I tried reversing it to a switched neutral but it is hard to tell what is going on voltage wise and the outlet seems to be on all the time except during the switch process.

Impotant things to know are: There are no appliances on this circuit, the oven on the main floor is 240v but it is on a different circuit. I do have this box isolated to the same circuit so when I flip the breaker, everything is dead. Also I have replaced all switches so they are new, I have taken the light fixture out and it is just a bare lead to test voltage. Also one other thing I found odd. I seem to get voltage on both of the switching legs coming from the 3 way switch(light colored screws) when I switch the switch one leg goes to half voltage.

I am not sure if this is a crossed wire, a corroded connection, or if I am wiring things wrong. I have tried reversing the positive lead going to the switch(going to the opposite switch first) This allowed me to switch the other 4 lights on the circuit on and off with the switch.

If it matters I plan to make this switch control an outlet that will have a light plugged into it. Rather then go back to the old light fixture.

Thanks

This is an attempt to draw out what I think is the way this circuit is laid out. All the wires shown go to the same metal box. All the connections are shown as an orange wire nut.

The wiring diagram looks fine. All I can offer is to take the circuit wiring apart, begin at the beginning of the circuit testing for proper voltage, and connect each segment of circuit and test before connecting the next segment, so on and so forth, until the problem is found.