Low voltage in wall switch

From your description, that's a three way switch. The wiring that you described have is not suitable for installing a receptacle at that location, without a modification to the wiring there, or someplace else on the circuit, such as the location where the mate to that switch is installed. Three way switches are used where you need to control a light from two (or more with the addition of a 4 way switch at each extra location) different locations.

To install a receptacle, you need 120 volts at the location where you want the receptacle. You said you measured only 80 volts - that won't provide the needed power.

Ed

If the light comes on at full brightness it could be a measurement error or a defective meter. If one of the switches gets warm to the touch the switch has gone bad.

Is there any possibility of a lamp dimmer somewhere in the circuit?

Could be, anything can break, but more often its a switch.

I'd recommend careful troubleshooting by an knowledgeable person, if not a good electrition..

Note that codes inspectors want to see a functioning 3-way switch at the top and bottom of stairways in many cases.

If you read 80 volts in there, what was the reading between? If the power is brought into the box that the load (light) is attached to, and the switch legs are running "out" to the switches, and if your house is old enough to not have a ground, then you really have no reference to ground or neutral available, and your reading could depend on whatever load is on the leg measured, a high resistance fault or any of many other scenarios. There are some ways to convert that circuit so it will support an outlet without running any new wire, but they involve line-carrier switching or an alternating relay or such. If you are having trouble with this level of knowledge, you should definitely get some pro help in there.

| Note that codes inspectors want to see a functioning 3-way switch at the top | and bottom of stairways in many cases.

Why do they want a 3-way switch there? I don't recall seeing anything in the code that requires a 3-way switch.

two switches controlling the same lights normally requires 3-way switches

|> | Note that codes inspectors want to see a functioning 3-way switch |> at the top |> | and bottom of stairways in many cases. |>

|> Why do they want a 3-way switch there? I don't recall seeing |> anything in |> the code that requires a 3-way switch. | | two switches controlling the same lights normally requires 3-way | switches

Replace "normally" with "typically" and I'd agree with you. However, that is not a required configuration. An inspector should want to see a switch that will turn the stairway light on and off at each end of the stairway, including midway access landings where two or more segments are controlled in common. It should be verified that turning the light off at any point does not preclude turning it back on at any other point.

If have personally found that 3-way switches pose a minor hazard because of the incorrect orientation of the switch half the time. The typical hazard scenario is carrying things that require two arms, and trying to turn the light on or off and finding an incorrect switch orientation. This could be made worse if a stairway is involved. This hazard can be a major one if what is being carried is a baby.

My house plans for what I will be building in the future specify that no

3-way toggle switches will be allowed in most circumstances. Instead, I will be using those switches that settle into the middle position by the spring force, and make momentary contact to separate wires when pushed up or down. That will then activate a contactor that controls the actual power current. The control side will be 12 volts.

For stairways, there will be two separate contactors controlling the light each each end of the stairway. Thus, if one contactor fails, chances are the other will continue to work for a while. Additionally, motion sensors will be used for stairways to ensure the light comes on and stays on as needed. All switches and sensors will control all contactors for that one stairway.

What if the failure is in the "on" position?

I've heard of this before, so it may be a local thing. Also, many inspectors "don't need no steenkin' code". When I built my garage the building inspector threw all sorts of things (>$1000 worth of "things") at me that weren't code. There is usually little choice but to make inspectors happy.

you got that straight :) ... this month a surprise inspection at a building built in 1949 or before turned up this requirement among others including add a wall switch for a chain pull light fixture and eliminate all visible runs of Romex. (change to conduit or armored cable)