Red Wire Reading 44 Volts (was 120 volts)

[Caroline]

Up until a month or so ago, all of my house's electrical receptacles worked fine. Now, one electrical receptacle in each of my house's two bedrooms does not work. All other receptacles in the house work and have readings of about 120 volts.

The two receptacles that do not work have "in common" a red wire.

The red wire to white wire (or neutral) voltage readings are all about 44 volts.

The black wire to red wire voltage readings are about 66 volts.

The two bedrooms and living room all have ceiling fans and ceiling light fixtures. These three rooms also have a 3-switch control near their entrance. One switch controls power to the receptacles. Another controls the fan. And the third controls the overhead light.

My area has seen more rain than usual. On the other hand, humidity is very low here; any moisture dries quickly.

Why would the red wire suddenly fall to 44 volts (instead of the usual 120 volts) in the two rooms?

All suggestions welcome. I will be troubleshooting further today.

[Me]

What is the voltage from black to white? I am assuming we are talking about the wires in the switch box? what is the voltage from red to ground as well as black to ground.

[Joseph Meehan]

You're using a nice new digital meter from Radio Shack, right? They are great meters, but they are very high internal resistance. Wires running close to active AC wires will pick up some current. It can easily be 66 volts, but almost 0 amps. You will only be able to read this when you are using a sensitive modern meter and that line is otherwise dead. My first guess is the line is dead.

Another possibility for this kind of voltage is a floating neutral.

Easy way to tell. Put a load on that line, a 120V light bulb is fine, then test the voltage. If it is really 44 or 66 volts it may glow and you will still get the same voltage measurement. Otherwise it will not glow and you will now read 0 volts.

Funny that 44 + 66 = 110 Which may indicate the floating neutral.

[Caroline]

"Me" wrote

120 V

Yes. The switch box being the electrical fixture that holds two outlets. One outlet works; the other does not.

The house has two such fixtures. Both have a red wire.

44 V

120 V

[Caroline]

Everything you suggested checks out as follows:

The meter is from Radio Shack, digital, and just a couple years old.

I did the test you described, and the voltage from red to white dropped from "44 V" to near 0.

Okay. I am reading up on this now, but your further suggestions to eliminate this floating neutral are welcome.

[Chris Lewis]

According to Caroline :

This doesn't imply floating neutral. If red is floating 44V away from neutral and ground, assuming in phase, it'll be 66V away from hot.

Simple voltage division.

With high impedance meters (especially cheapy digitals), a wire not connected to anything will often show surprisingly high voltages. It's acting as an antenna, and the meter doesn't load it down hard enough to show the real value.

I simply assume that the red wire has opened somewhere.

If the neutral is more than a few volts away from the ground, _then_ you have a problem with the neutral or the ground.

[Joseph Meehan]

Your results do not indicate a floating neutral.

A floating neutral is one where the neutral wire is no longer connected to the neutral bar in the breaker box.

The indication is a bad connection or break somewhere at or before those outlets that are not working. I would start by pulling each to assure that the problem is not there, taking the usual precautions to stay safe and do not assume that there are no live wires in those boxes.

Maybe before that I would check all the GFI's you may have. Look in each bath, and the kitchen, also check the breaker box (note make sure it is not just a breaker that tripped. A lot of people have been fooled by a GFI that tripped and they did not notice also controlled another device that normally would not be GFI protected.

[Joseph Meehan]

Hold on here. One outlet = ???. Are you talking about one duplex outlet (room for two plugs) or are you talking about two duplex outlets, room for 4 plugs.

If you are talking about a single duplex outlet, then take a look at the tabs between the upper and lower screws on each side. Are they still connected? Are there different wires to each? Is there now or maybe in the past, a switch controlling one of the duplex pair?

[Caroline]

"Joseph Meehan" wrote Caroline wrote

Yes. Sorry. I thought "one outlet" meant "holds one plug."

This was the problem. The switches must have been changed while I was vacationing recently and a house sitter was in charge.

Big "doh" on me. :-(

Thanks to all for your assistance.