Flashing low energy light bulbs?

  Pine Man 08:40 06 Dec 2009

Wasn't sure where to post this but here goes.

I have three wall lights in my living room and all are fitted with low energy bulbs. Last night when it was completely dark I noticed that there was a feint flash from one of the bulbs, which was turned off. This morning it was still flashing so I changed it over with another wall light fitting and found that it is the actual bulb that flashes wherever it is put.

How can that be?

  Pine Man 09:15 06 Dec 2009

It comes from the mains. Two parallel conductors separated by insulation forms a capacitor. A capacitor will block DC current, but with AC power, some current can "leak" through. In a two or three-way switched system, there will be two switched live conductors running in the same cable, and this cable run can be several metres.

The leakage current is far too small to light a normal lamp, but the electronics driving the low energy lamp stores this power up until there's enough to strike the lamp.

  bri-an 09:29 06 Dec 2009

Intrigued by your 'solution', do the other low energy lamps not do the same, if put in the same socket?
I would have thought that if the wiring was causing the leak current to flow, then any low energy bulb would flash in the same way. If only the one lamp suffers the effect there has to be something about that lamp...?

  dms_05 09:38 06 Dec 2009

Pine Man - what happens if you replace the flashing bulb with another low energy bulb, does another bulb in the 3 bulb system begin to flash? It might be the one that flashed requires a lower energy input to flash compared to the other two so flashes where ever it is used.

  Pine Man 09:42 06 Dec 2009

What I posted above was from a search I did. I don't profess to understand it;-)

I have been playing around a bit and it is only the one bulb that does it wherever it goes. It flashes very faintly about every couple of seconds or so. I don't know how long it has been going on but the bulb has been in use for about a month.

It is clearly able to get power from the circuit somewhow as when the fuse is removed the flash stops.

  John B 11:45 06 Dec 2009

They have been mentioned elsewhere as being more prone to behave as you describe.

  Pine Man 12:17 06 Dec 2009

Yes it is.

All of the low energy bulbs I have are Phillips. It's lucky they don't all flash or it would never get dark:-))

  John B 13:53 06 Dec 2009

(very interesting topic by the way)it is caused by the wiring and is usually found on wiring layouts associated with multiple switches (landing light circuits and the like)but not always.

One post elsewhere was from someone who had the problem with the main light in the bedroom.

Each problem does seem to be associated with Philips' bulbs.

  wiz-king 15:10 06 Dec 2009

I have one as well, the one in the kitchen will sometimes flash a couple of times after it is turned off but only if the kitchen is hot and the light has been on for a while.

  skeletal 14:27 09 Dec 2009

Yes, I’ve seen this as well. It was in a bedroom, really helpful if you want to get to sleep. I had to replace it with a proper bulb when we fitted a dimmer switch.

It could be capacitive current; I couldn’t be bothered to try to work out what it was at the time.


  Pine Man 14:34 09 Dec 2009

Thanks for your input.

I have just moved the bulb to a different light fitting so it isn't as noticeable.

Recent checks suggest that it never stops flashing!

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