[kupe]

Hey gang-

Thought I'd seen it all in "this old house" but I'm stumped on this one.

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.

What's even more strange is that we never noticed this, at least with regard to the operation of the old fan and light. One would think that at the least the light would have continued to glow dimly even at 60 volts. Maybe the fan would even turn slowly.

It was only when using my digital multi-meter and trying to find the correct circuit breaker that I discovered this. With the circuit breaker off, it goes (not surprisingly) to zero voltage.

Ideas anyone?

Thanks!

Kupe

 

[SD515]

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

 

[oberkc]

Swith loop with switched neutral?

 

[kbsparky]

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

 

[Daddyshammer]

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

 

[AllanJ]

Q:

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

A:

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?

 

[kupe]

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

 

[kupe]

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

Kupe

 

[Daddyshammer]

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

 

[a7ecorsair]

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?

 

[shazapple]

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.

 

[druminman]

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.