On 26 Jun, 10:13, "Arfa Daily" wrote:
"James Sweet" wrote in message

news:A61gi.6303$oo5.5110@trndny09... When it is switched off, it blinks every few seconds. So, I guess
that there must be a problem with the switch If it is passing nothing
then it would seem impossible for the bulb to do anything. I did not
notice any problem with the previous incandescent bulb but I guess
that if the switch is leaking a tiny amount, the filament would glow
too little to be seen.

Is one of the switches illuminated? Those will pass enough current to
slowly charge up the filter capacitor in the fluorescent bulb and cause it
to blink.

If it's leakage from anywhere, a bog-standard electricians neon test
screwdriver should show that up. Or try wiring a mains rated neon indicator
straight across the lampholder without the lamp in place. If it glows, you
have leakage either across one of the switches, or between lives. Bear in
mind that with a two way circuit, there are two wires, one or other of which
is always live, running (normally) in a common cable sheath, between the two
switches. Also bear in mind that the poster said in his third reply that not
only is there a two way switch at either end of the landing, there is
actually a third switch at the half way point where a corridor joins the
main hallway. I'm not quite sure how you factor a third switch into a
'standard' two-way circuit, but it occurs to me that it might well be
'stealing' its live either from a second lighting circuit, or from some
considerable distance around the lighting circuit, from where the main live
for the circuit is taken. Either way, that third switch must join into the
actual landing light circuit, via some kind of junction box, which may be
part of the light fixture ceiling rose, if that's nearby, or a separate
entity in the loft. It could be potentially another place for some kind of
leakage taking place.

I do have a mains rated neon screwdriver so that will be one of my
first tests.

The third switch puzzled me when I moved to the house. I researched
how it could be done and I have posted a description elsewhere in the
thread. The system is rare in the UK but I read that it is common in
Spain and some other places. I have not yet checked whether my house
is wired as described but flicking any switch at any time will change
the state of the light so the switches are not simply in series or
parallel. If the wiring is as expected, there will be two alternative
live wires (always one live and one dead) running together for a
considerable distance, rather more than the length of the landing . A
leak between these two would explain the problem but not cause a fuse
to blow or an RCCB to trip.

Did anyone see in the Sunday paper, an article regarding these CFLs causing
pre-fit symptoms to epilepsy sufferers ? Seems it's becoming common, and the
same people don't suffer with ordinary flourescents. Some research suggests
that it might be to do with the (apparently) very uneven spectral response
of the tri-phosphors used to try to get an 'incandescent' colour. Hmmm ...


--
Seán Ó Leathlóbhair