I have a 14w Nvision brand compact fluorescent bulb on a three-way switch
circuit in my stairway that pulses very weak light, from near the base of
the discharge tube, about every second, when the switch is in the "off"
position. Looks like a weak strobe light.
I checked the "off" voltage across the empty socket - it was about 5v. One
of the three way switches has a lighted toggle, for what it is worth. The
lamp fixture is a can light, new, and seemingly properly wired but cannot
tell if the body of the unit is grounded, as only the hot and neutral feed
wires are visible on my side of the metal fixture reflector.
All I can figure is the low voltage is charging a capacitor in the bulb
base, and the capacitor periodically discharges its stored energy into the
How can I trouble shoot (if this is necessary for safety) the source of the
low voltage in the lamp socket?
And is this in any way a fire danger?
This item has no significant fire danger.
The biggest problem is "leakage current" through "cable capacitance"
shortening the life expectancy of the "bulbs". That itemmay be as low as
If the "bulbs" are UL-listed and used in a manner not other than is as
directed, I woukld not worry much. Screw-base CFLs appear to me to be
generally subject to UL by requiring integral ballasts. The category
that UL has for these is "self-ballasted lamp", give or take a hyphen and
a space or two.
- Don Klipstein ( email@example.com)
Because of the lighted toggle below, maybe you can skip the step below
or save it for later.
Hmmm. You should measure with a meter with a needle. Everyone here
says that digital meters give false readings because of induced
Or with enough connecting things, I think you can put an incandescent
light in series with the socket and an ammeter. 110 watt lightbulb
would be about an amp at 110 volts, so at 5 volts, it will be 1/20th
(50 milliamps) or 1/22nd of an amp, if there is really 5 volts. You
can calculate the actual voltage from that.
I think could well be significant.
We just had a thread about 3-way toggle with pilot ligths. But yours
just has a lighted handle, right. With a regular bulb, the light is
on when the switch is off, right, and vice versa?
And that probably uses a very small neon bulb. If it were an
incandescnent bulb that was in the circuit, then measureing the
voltage across the empty socket would give the full 110 volts. I have
to think about this. How can it show only 5, just because it is neon.
Go do that step I said you could skip. :) So we know what the voltage
really is. Or do the step below and don't worry about why, just how
to fix it.
Well, you could pull the 3-way out and replace it with a two way, or
a 3-way with no light, or most simply, you could disconnect one of the
two wires out of three that are connected when the switch is in the
off position. Turn the fuse or breaker off and when the wires are
separated, turn the fuse back on again.
I don't think so, but it may wear out your bulb more quickly. I guess
it doesn't take any more electricity than the lighted swtich did in
the first place. If that is the reason.
I have a CFL on a 3-way, but it's not a lighted switch.
I'm sure this will come up a lot as time goes on.
I'm beginning to think the Luddites* may have known what they were
about. Stuff like what's being discussed on this thread says to me
things are getting too damn complicated.... <G>
I get shivers when I think about all the electrons doing their things to
keep my car engine running nowadays. When I first became a gearhead, all
you had to know was that if you had "gas and fahr", the engine would
probably run, and you could tell if those were there with just the
senses the Good Lord gave you.
Last month I had to shell out a bundle for a valve job on daughter's V6
Olds. It felt like it was running fine, but it wouldn't pass inspection
because the diagnostics said one cylinder was running "weak". A
compression check showed it was off, but I was flabbergasted to dig in
and learn that the computer could tell that because the weak cylinder
caused the crankshaft's rotation to slow down a tiny bit during that
cylinder's power stroke, 'cause it continuously monitored crankshaft
angle throughout each revolution. Then I remembered the reason why
they've had harmonic balancers on the ends of car engine crankshafts for
The exhaust valve in the affected cylinder, and it's seat also, had a
single "ding" on their mating surfaces. The likely cause was a "plug and
wire change" last year which was shortly followed by the engine running
very rough rough because the stationary electrode fell right off the
plug in that same cylinder. A new plug "fixed" the problem, but I'm
feeling that little steel electrode bounced into the precicely wrong
place and F'd up the valve and its seat.....Remaining unoticed until
state inspection time rolled around almost a year later, when it was far
too late to try and raise a stink over that defective spark plug.
The word "luck" in our family is too often spelled with just three
letters, B-A-D. <G>
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