On Mon, 25 Jun 2007 07:45:29 -0700, 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).

Your switches are wired wrong (they are switching the neutral (or
cold) side of the line, not the hot side. As well, you seem to have a
leakage problem in the circuit as well. This leakage could be a switch
or some other device or part.

First step is to make 100% sure the switches are in the hot side of
the circuit. That will likely solve your problem immediately. I'd
guess there is a chance much of your house is not wired correctly from
your description...

Not sure what building codes/wriing codes you have in the UK, but in
the US this circuit would not have passed a building inspector.