Flickering Low Energy Bulb

Nov 23, 2008 5 Replies

The low energy compact fluorescent bulb in the hall flickers when it is switched off. All the wiring looks correct so why does it flicker when the power is off. The light switch it the type with a light sensor in it but it is usually in the normal mode, ie not operated by the sensor so what is wrong.



Kevin


Do you mean it flashes once every few minutes, or more regularly than that? It generally happens when a long run of cable allows capacitive coupling from a permanent live into the switched live, then a capacitor within the fluorescent bulb stores this charge, until there is enough for it to briefly light up, then the process starts again.

This is an FAQ. Look back in Google Groups and you'll find piles of discussion about it.

In summary - it's normal, it's caused by capacitive coupling in the wiring, and it's nothing to worry about.

electronics in them rely on a path to neutral through the lamp.

sensor switch which I'd bet has no neutral connection and uses leakage through the lamp to power itself. It probably powers itself in "normal" mode as well. I wrote a very long and detailed reply recently to a thread on "Outside light with PIR" which is directly related to this problem. In short use a different make of CFL, or a normal bulb, or a bleed resistor.

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