voltage bypassing switch?

I think there's a ghost in my house.
Sitting in the dark, I occasionally witness a compact flourescent bulb light up very faintly, for no more than a second. Two lights (on two different circuits) do this. The first is in a stairwell and switched by two three ways and one four way. The second is switched by two three ways.
I've had two electricians look at it and find no apparent problems with the wiring in the switch boxes. I should state for the record though that I wired the switches for the first light, and I'm not an electrician. One of the fixtures had the black and white wires reversed, but correcting this didn't change anything. The switches for the first fixture are all brand new. Those for the other are 50 years old. The house is wired with BX cable, except for renovated areas, including one of the lights. Both lights are grounded just fine.
Here's the puzzle: using a meter, the lights register 30V from black to white when the switches are set to turn the light *off.* Does anyone have thoughts on what could possibly cause this?
By the way, one electrician noted that when one touches the black to ground, nothing happens -- no spark, no short, nothing, so maybe the meter is misleading us, but then the other electrician registered the same thing on his meter, and remember, the bulb lights up.
Ultimately, I'll probably just have an electrician rewire the whole damn circuit, but I sure would like to know what's wrong first....
Thanks for any advice
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I don't have a real answer for this but I do know that static, or stray electricity , will cause this to happen, Honest, go ahead and rub a tube on a staticy sweater in complete darkness, it will glow with the strokes against the sweater. I think your right about the wiring being goofy, but I'm not an electrician, just a rental property owner that does most of his own work. Clark
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If the BX is really old, you might want to replace that. I had some old BX (I'm guessing 40 years old) that was going up the chase inside an exterior wall to my home office, showed some rusting on the steel armor, and that circuit was never quite right. I ripped it out and replaced with new BX and it's fine now.
-- Paul
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Probably nothing wrong. The voltage is an induced voltage caused by wires running close to each other. The meter is most likely a digital voltmeter and they require very little current to show a voltage. Anytime two wires are close to each other a very low grade transformer or capacitor is made. Not enough to have much current but enough to show up as some voltage on a digital voltmeter. If an older analog meter is used such as the Simpson 260, as you change the switch for the voltages , the meter needle will stay in about the same physical place, but the voltge will appear to change a lot.
It does not take too much power for a compact flourescent bulb to flash for a second or so. Static or maybe even the refrigerator or airconditioner will produce a spike when the motor starts to do this.
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Wonder if he lives near this guy with the Tesla Coil
http://physics.fullerton.edu/~physicsclub/tesla-coil.jpg
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Used to be somewhat easily made. 30+ years ago I think we used a transformer from those liquor store neon window signs. If I recall they had some really good step-up.
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Don't bother. I think the whole idea is charming, like squeaky floors or rattling pipes.
Gives the house character, it does.
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wrote:

Ralph's post above has the right idea.
It is current crossing between long runs of parallel wires via the wire to wire capacitance.
CFL's often do this.
If it is a nuisance then change back to incandescent lamps.
Ross
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WHAT? ...AND DESTROY THE PLANET?
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Other posters have correctly identified induced voltage as the most likely cause.
With some CFL electronic ballast designs, this voltage will slowly charge a filter capacitor inside the CFL until it reaches a critical threshold, at which point the lamp will flash on momentarily.
The voltage may be due to the design of the 3/4 way switches, so you can try changing these to a different design. Or change the CFL to one that has a different ballast (e.g., quick-start vs. not-quick-start).
HTH.
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Or put one small incandesent bulb on the circuit.
Bob
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