Hello,

The cfl in the bathroom light has started flickering when switched
off. I'll get the step ladder out later and replace the bulb and see
what happens. There has been no changes to the wiring, so that cannot
be the cause.

The light is operated by a cord switch and at first I thought may be
the switch was faulty and passing a small current but I now think it
might be a bulb problem. When the light is switched off it flashes
every few seconds but left for a few hours, the flashing seems to
stop. If the switch was passing a small current, the flashing ought to
be continuous.

Do cfls have a capacitor? I'm wondering whether something charges up
when the light is on and then gradually discharges, causing the
flashes, when the light is switched off. After some time whatever it
is "flat" and so the flashing stops. Would that make sense?

Thanks,
Stephen.

Stephen wrote:

The cfl in the bathroom light has started flickering when switched
off.

It's a well known effect, there *is* a capacitor that can slowly charge
from induced current from nearby wires, and then give a flash as it
eventually reaches sufficient level to briefly drive the lamp.

You say no wiring changes, but perhaps you've replaced a nearby
incandescent lamp with another CFL, and where previously the induced
current was going un-noticed into that filament, it's now "easier" for
it to flash the bathroom CFL? Or maybe you've left a nearby 2, or 3 way
switched lighting circuit in a combination you don't usually?

These weird effects seem to be quite common according to friends of mine,
even a nearby thunder storm seems to do this sort of thing, presumably by
induced current charging up a capacitor.
I'd have thought these lamps or fittings ought to have a very high
resistance resistor across any capacitor to stop it.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Andy Burns" wrote in message
o.uk...
Stephen wrote:

The cfl in the bathroom light has started flickering when switched
off.

It's a well known effect, there *is* a capacitor that can slowly charge
from induced current from nearby wires, and then give a flash as it
eventually reaches sufficient level to briefly drive the lamp.

You say no wiring changes, but perhaps you've replaced a nearby
incandescent lamp with another CFL, and where previously the induced
current was going un-noticed into that filament, it's now "easier" for it
to flash the bathroom CFL? Or maybe you've left a nearby 2, or 3 way
switched lighting circuit in a combination you don't usually?

On Wednesday, March 12, 2014 6:29:20 AM UTC, Stephen wrote:
Hello,
The cfl in the bathroom light has started flickering when switched
off. I'll get the step ladder out later and replace the bulb and see
what happens. There has been no changes to the wiring, so that cannot
be the cause.
The light is operated by a cord switch and at first I thought may be
the switch was faulty and passing a small current but I now think it
might be a bulb problem. When the light is switched off it flashes
every few seconds but left for a few hours, the flashing seems to
stop. If the switch was passing a small current, the flashing ought to
be continuous.
Do cfls have a capacitor? I'm wondering whether something charges up
when the light is on and then gradually discharges, causing the
flashes, when the light is switched off. After some time whatever it
is "flat" and so the flashing stops. Would that make sense?
Thanks,
Stephen.

http://wiki.diyfaq.org.uk/index.php?...ional_flashing


NT

On 12/03/2014 06:29, Stephen wrote:
Hello,

The cfl in the bathroom light has started flickering when switched
off. I'll get the step ladder out later and replace the bulb and see
what happens. There has been no changes to the wiring, so that cannot
be the cause.

The light is operated by a cord switch and at first I thought may be
the switch was faulty and passing a small current but I now think it
might be a bulb problem. When the light is switched off it flashes
every few seconds but left for a few hours, the flashing seems to
stop. If the switch was passing a small current, the flashing ought to
be continuous.

Do cfls have a capacitor? I'm wondering whether something charges up
when the light is on and then gradually discharges, causing the
flashes, when the light is switched off. After some time whatever it
is "flat" and so the flashing stops. Would that make sense?

Thanks,
Stephen.


I have one that I know flashes when switched off. I have replaced it
with an LED bulb, now that 1000 lumen ones can be bought for less than
a tenner.


--
Michael Chare

On Wed, 12 Mar 2014 08:04:00 -0000, "Brian Gaff"
wrote:

These weird effects seem to be quite common according to friends of mine,
even a nearby thunder storm seems to do this sort of thing, presumably by
induced current charging up a capacitor.
I'd have thought these lamps or fittings ought to have a very high
resistance resistor across any capacitor to stop it.
Brian

Thanks for all the replies; they have been very interesting.

It seemed curious to me that the flashes only occurred at night. I
wondered if perhaps they were happening all the time but were less
visible during the day. However I don't think that is the case. I did
wonder whether like one reply said, it is dependant on another circuit
being in a certain state nearby, so perhaps it only happens when
another light nearby is switched on?

However this morning it occurred to me that there is a fan over the
shower which is switched by the light. The fan has an isolator and
SWMBO switches off the isolator and only switches it on when she has a
shower, so possibly there is something amiss with the fan and it is
passing current from its permanent live to the switched live which is
causing the flashes. I will investigate more.

Thanks,
Stephen.