I replaced some existing incandescent bulbs by LED bulbs, then noticed that they do not switch off completely but still glow dimly.
Checking the voltage at the lamp socket with a high-resistance electronic multimeter, I get a reading of 48v!! A few volts might be OK
-- induction, stray voltages, etc., but 48V!!!
This occurs in two different rooms, but I think the various lighting circuits are all connected to one breaker.
What could cause this?
Perce
its the meter, take a walk around high sensitivity meters will show 60 volts under the neighborhood power line........
connect a 100 watt light bulb with the meter voltage will go away.
relax yours must be one of the most frequent questions asked.
LED? You don't mean complact fluorescent? I havent' seen LEDs that fit wthout changes.
But in the kitchen with a timer in place of the wall switch, I couldn't get my CFL to turn off. Do you have a timer in the circuit.
A timer in each room, and on lamps, seems unlikely.
I agree, sounds like a bad ground (neutral)
I'm going to guess here that you have some kind of electronic switch, i.e. a dimmer or something similar. As long as there is enough voltage to turn on the LEDs, a small leakage current from an electronic switch could make them glow dimly.
Yes, a timer, an electronic on/off timer.
48V at high impedance means absolutely nothing.
That's it. I bet your timer was designed to not require a neutral. As such, it has to draw a little current through the lamps to power itself even when off. x-10 switches are notorious for that, but any electronic device that gets wired in place of a switch and does not require a neutral connection will do it. Usually placing a small incondescent bulb (like a 7 watt night light bulb) or a resister in parallel with the LED's will solve the issue. Or, get a different timer that requires a neutral (if the box in question has a neutral wire in it, Or, get rid of the timer if you don't really need it.
On Sun, 05 Apr 2009 22:44:55 -0500, AZ Nomad wrote Re Re: 48 volts with switch off!:
Why is that?
Yes, agree that the electronic timer is what's causing the bulbs to light dimly. Most of those type devices are designed to work without a neutral, so they rely on some very small current always flowing. In the case of incandescent bulbs, it's not a problem. But CFLs, LEDs take so little current, it's enought o start to light them. If you look at the data sheet for that electronic timer/switch it most likely says it's for incandescent use only.
switch is off!
I agree its the timer. years ago one caused me wierd troubles so I tossed it and went with a old neutral style with mechanical switch it still working fine today. at least 15 years after install
Which one? The neutral wire is white, the ground is bare. One or the other, please.
Cause you can have 48 volts, at zero load. But not enough working amps to do anything useful.
LED screw-in replacements for incandescent bulbs. Our local Sam's Club has a few different varieties of them. I have a few that are claimed to be 45W equivalent in light output for a consumption of 3.5W. The light is somewhat blue, but it's fine for my purposes and works fine as a replacement for the previous 50W incandescent flood.
No timer. Just an ordinary mechanical wall switch.
Perce
No. Regular "mechanical" wall switch.
Perce
No timer or dimmer. A regular wall switch.
Perce
No timer or dimmer. A regular on/off wall switch.
Perce
No timer or dimmer. A regular on/off wall switch.
Perce
It doesn't indicate any current flow or even potential for current flow. Voltage alone, measured with a high impedance meter is little different than static electricity. Leakage from capacatance between insulators will throw off a high impedance meter.
Put a 1K resistor on it, and the voltage will drop to zero.
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