# Half Voltage at outlet when switch is OFF?!?!



## SD515 (Aug 17, 2008)

Old house with ungrounded circuits? Bleed-through an old switch? Got knob & tube in the house?


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## oberkc (Dec 3, 2009)

Swith loop with switched neutral?


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## kbsparky (Sep 11, 2008)

Phantom voltage reading. Common when using high-impedance input digital testers.


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## Daddyshammer (Jul 22, 2009)

I believe the switch is wired incorrectly. I did it when I wired my recessed lighting in my living room on a 3 way switch. Recheck and test.

J-Daddyshammer


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## AllanJ (Nov 24, 2007)

Q:


kupe said:


> It was only when using my digital multi-meter and trying to find the correct circuit breaker that I discovered this.


A:


kbsparky said:


> Phantom voltage reading. Common when using high-impedance input digital testers.


If you have a small incandescent lamp (perhaps using a bare socket with alligator clip wires) connected across the two meter probes, does it light up dimly or does the voltage measured go to zero?


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## kupe (Apr 14, 2011)

Daddyshammer said:


> I believe the switch is wired incorrectly. I did it when I wired my recessed lighting in my living room on a 3 way switch. Recheck and test.
> 
> J-Daddyshammer


I thought that might be it, but I checked and it's a simple 2-way switch. I went ahead and replaced it on the chance it might have been faulty, but no change.

Kupe


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## kupe (Apr 14, 2011)

Thanks everyone for the quick replies- I'm in the process of checking them all out.

Kupe


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## Daddyshammer (Jul 22, 2009)

Somewhere in the circuit is a constant flow if power. Kinda stateing the obvious here, but that is what you need to look for. 2 way is easier than a 3 way, with less wires. Somewhere this switch isnt grounded. Try getting a new one and start off fresh.

J-Daddyshammer


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## a7ecorsair (Jun 1, 2010)

kupe said:


> I'm in the process of replacing an old (1950s) ceiling fan and light assembly. Here's the problem. The ceiling box is "hot" with 60 volts even with the wall switch off. Wall switch on- all normal at 120 volts.
> 
> With the circuit breaker off, it goes (not surprisingly) to zero voltage.


In your description you say you have 60 V in the ceiling box with the switch off and 120 V with it on.
Power has to be fed either to the ceiling box or the switch box. If power is fed to the ceiling box then you would have 120 V all the time regardless of the switch position. Since you can change the voltage reading with the switch, *maybe* the power is fed to the switch.
Since this is a light and fan, how were these two functions controlled? Are there two switches or does one operate from a pull chain?
How is this place wired, with romex cable or something else? In the ceiling box, how many wires - individual wires not cables - do you find?


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## shazapple (Jun 30, 2011)

I had this exact problem while switching a light fixture. I spent an hour trying to figure out why there was 72 volts in the circuit with the switch off, and then I tried another multimeter which read 0 volts. I licked it just to be sure (just kidding!). Either the battery on my first multimeter was bad, or it went bad because it's a cheapo.


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## druminman (Mar 26, 2011)

I'll second the earlier poster's comment that it is phantom voltage. The can be cause by induction of crossing circuits, etc. If you have a wireless current meter, you'll find that even if you dead short your circuit with the switch off, it will only pull maybe 100 milliamps.

I used to work in a research laboratory where many of the measurements were on the order of a few millivolts, and we would often spend much effort and money trying to isolate 60v or 120v phantom readings.


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## Glenegade (5 mo ago)

I had this issue, 124V with the switch on, close to 60V with the switch off. So neutral to ground, I had millivolts, then hot to ground, 124V, went to the switch, and I had nothing with the switch off, or on, even though the light was on. The switch was wired the through the neutral.


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## betelgeuse (Jan 17, 2020)

Induced ("phantom") voltage.


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## AndyGump (Sep 26, 2010)

11 years too late for this thread but I was going to say that the OP's problem was probably that someone wired the switch to the neutral.

Andy.


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## Glenegade (5 mo ago)

AndyGump said:


> 11 years too late for this thread but I was going to say that the OP's problem was probably that someone wired the switch to the neutral.
> 
> Andy.


Could do someone well who's looking now, that's why I came on now, 11 years later. I'm just glad someone started the topic


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## Glenegade (5 mo ago)

This is also a big lesson, that just because a switch is off, doesn't mean there's not electricity in the socket, as a friend of mine who doesn't work electrical was trying to convince me


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## C'est Moi (Jan 5, 2022)

Is the switch a dimmer or fan speed control? If so it would not be uncommon to read voltage up there but it is a phantom voltage. What I mean by that is that if you tried to connect a light fixture to it it would not light as it would if there were truly 60V- it would light but it would be dim.


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## C'est Moi (Jan 5, 2022)

Dang-- I should have read the posts to see that this was an old thread...


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## Almost Retired (5 mo ago)

C'est Moi said:


> Dang-- I should have read the posts to see that this was an old thread...


he has a switched neutral
a cpl ppl caught it , most did not

very common way to do it in the 50's
no ground wire in the ceiling box to cause danger
dont ask me why it was common .... i have no idea but i have seen it at least a hundred times just in my area


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## C'est Moi (Jan 5, 2022)

Glenegade said:


> This is also a big lesson, that just because a switch is off, doesn't mean there's not electricity in the socket, as a friend of mine who doesn't work electrical was trying to convince me



If this is phantom voltage then there you would not get shocked.


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## AlexFullerton (3 mo ago)

Is it the old knob and tube wiring?


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