Hi, this isn;t that uncommon a problem with low energy bulbs. Its
probable that there is a voltage induced into the 'dead' circuit by
cables running in close proximity to one another. Typically this
occurs on long cable runs for hall/landing circuits.
The way I'd bottom it is to use a DVM across the lamp socket & see
what voltage is present. You shouldn't be able to draw any current (to
speak of) from a capacitive or inductive coupling.
What happens is that theres enough voltage for the tube to strike but
no capacity to draw current, so it goes out until the voltage builds
up again.
You can buy suppression capacitors to overcome this (Note they are
special devices - don't try to bodge it!) but sometimes just swapping
with another LE bulb will do the trick.
If the problem isn't as described, you'd better get someone in to
check the wiring for contacts or earth problems.
Dale.

On Mon, 25 Jun 2007 08:04:04 -0700, Seán O'Leathlóbhair
wrote:

On 25 Jun, 15:56, "Ron(UK)" wrote:
Seán O'Leathlóbhair wrote:
On 25 Jun, 15:39, Ken Weitzel wrote:
Seán O'Leathlóbhair wrote:
On 25 Jun, 15:21, BH wrote:
On Jun 25, 10:03 am, Seán O'Leathlóbhair wrote:
I am not sure if this is an appropriate group for this question. If
not, please suggest a better one.
I have a light in the house which I have wanted to switch to a low
energy bulb for a long time. The hold up was that I needed a very
small bulb. At last, I have found a small enough bulb but something
odd occurred as soon as I put it in.
When it is switched on, it works as expected.
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.
I have a few questions:
What is going on? Is a tiny current leaking, building up a charge in
a capacitor somewhere until a sufficient voltage builds up to spark in
the bulb and discharge the capacitor, and then the cycle repeats.
Is it safe?
Will it wear out the bulb very fast?
Is it likely to be enough to replace the switch? (Actually three
switches can turn this bulb on and off).
Might I have to replace the wiring? (Much harder than just replacing
the switches)
--
Seán Ó Leathlóbhair
Try the buld in another location. Give us moe information on the bulb.
Thanks.
Normally, I would immediately try to isolate the cause by moving
things around but, in this case, I dismissed the bulb as the problem
since I thought that if the switch was passing nothing when off (as it
should) then there was no way the bulb could do what it is doing. If
the bulb is at fault then it is not the only fault (or so I assumed at
any rate).
The brand of the bulb is Philips but I cannot tell you more until I
get home and look at it. I will post again later with fuller details
and the result of a test in another location.
Hi...

Can't help wondering - it's not possible that one of those
"switches" is a dimmer, is it?

Take care.

A good question but no.

It is a landing light. There are three switches, one at each end and
a third in the middle where a small corridor from the bathroom joins
the landing. All simple on off switches (well they must be changeover
switches but, from the user's point of view, they are just on off).

Sounds like leakage to me, there may be a measurable voltage floating on
the neutral. I has a similar problem with fluorescent emergency lights
last year. If you are in the UK it might be an earthing fault.


I am in the UK.

How does an earthing fault affect the lighting circuit? I thought it
was just two wire. The earthing for the house in general was checked
a couple of years ago when we changed the boiler. The gas engineer
said that a change was required but I forget exactly what that was.
The RCCB in the new fuse box is not tripping but does it apply to the
lighting circuits?