I've just replaced the landing light with a 60w low power one.
The light is switched from downstairs and upstairs.
In one of the "off" settings the light flashes every 3 - 4 seconds, in the
other "off" setting it doesn't.
The cable between the switches is Y (240) B R G (earth).
The flashing occurs when the red and blue are connected to the light side of
the circuitry.

I assume it is capacitance between the cables that is causing the problem.
Apart from rewiring with separate cables is there any other solution.

John

jks wrote:
I've just replaced the landing light with a 60w low power one.
The light is switched from downstairs and upstairs.
In one of the "off" settings the light flashes every 3 - 4 seconds, in the
other "off" setting it doesn't.
The cable between the switches is Y (240) B R G (earth).
The flashing occurs when the red and blue are connected to the light side of
the circuitry.

I assume it is capacitance between the cables that is causing the problem.
Apart from rewiring with separate cables is there any other solution.

John
It can be a problem with the cheaper bulbs. Try a more expensive one

It can be a problem with the cheaper bulbs. Try a more expensive one


This one was free from PowerGen

"jks" wrote in message
...
I've just replaced the landing light with a 60w low power one.
The light is switched from downstairs and upstairs.
In one of the "off" settings the light flashes every 3 - 4 seconds, in the
other "off" setting it doesn't.
The cable between the switches is Y (240) B R G (earth).
The flashing occurs when the red and blue are connected to the light side
of
the circuitry.

I assume it is capacitance between the cables that is causing the problem.
Apart from rewiring with separate cables is there any other solution.

John


It's got to be a Philips one, they have recently admitted to a problem with
the faulty starter circuit in the 18w variety. They are currently
exchanging then for people if you contact them via the website.

I too think you're seeing the effect of capacitive coupling (aka
crosstalk or pickup) between the individual wires in the cable. It's
interesting that you observe it only in one of the two "off" states - I
think I can see how that can happen - not that I can offer a fix
though.
The cable is probably 3-core and earth which is usually arranged as
colourA-earth-colourB-colourC across the cable. I don't think that the
coupling will be between colourA and one of the other colours as the
earth will supress it. That means that colourB and colourC are
coupling. My guess then is that when you don't see the effect colourA
is connected to the lamp with colourB and colourC as live feed and
connected to the switch. In the other off state colourB and colourC
are live feed and connected to the lamp, hence the coupling.

Other posters have suggested that more expensive CF bulbs don't do this
- I wonder if they have bleed resistors?
[In fact maybe there's a DIY solution there - a bleed resistor across
the terminals of the fitting].

It's got to be a Philips one, they have recently admitted to a problem
with
the faulty starter circuit in the 18w variety. They are currently
exchanging then for people if you contact them via the website.


It is a Philips. - 60w equivalent.

"Genie 6yr 11w"

"Calvin" wrote in message
oups.com...
I too think you're seeing the effect of capacitive coupling (aka
crosstalk or pickup) between the individual wires in the cable. It's
interesting that you observe it only in one of the two "off" states - I
think I can see how that can happen - not that I can offer a fix
though.
The cable is probably 3-core and earth which is usually arranged as
colourA-earth-colourB-colourC across the cable. I don't think that the
coupling will be between colourA and one of the other colours as the
earth will supress it. That means that colourB and colourC are
coupling. My guess then is that when you don't see the effect colourA
is connected to the lamp with colourB and colourC as live feed and
connected to the switch. In the other off state colourB and colourC
are live feed and connected to the lamp, hence the coupling.

Other posters have suggested that more expensive CF bulbs don't do this
- I wonder if they have bleed resistors?
[In fact maybe there's a DIY solution there - a bleed resistor across
the terminals of the fitting].


I measured the voltage using an analogue meter from the light side to earth.
The voltages were 40v and 75v in the two "off" positions (light removed). I
think the cable
arrangement is
123e. 2 and 3 connect live in one state ( capacitance is 2 - 1) and 1 and
3 in the other (capacitance 1 - 2 and 2 - 3).

A 123e arrangement would be very unusual. Every cable I've ever seen
has the earth in the middle.
Anyway I think the only solution is a bleed resistor of low enough
value to stop the cap in the CF lamp from charging or a lamp with one
built in. That said I've lived with our landing light doing the same
thing for years and I can't see that it's a problem worth fixing.