Replacement low energy lamps fail to work

[JohnD]

I meant of course a US light fitting installed in the UK

they do almost fit.

 

[Manyanga]

Thanks for these suggestions. I will make a fuller inspection the next time I visit. The bulbs are standard Philips LE bayonets. My daughter initially blamed the bulb-replacing skills of her partner, but repeated attempts to get the LEs to work in all the holders failed. Some worked, some never lit at all, some lit one day and failed the next.... Taking the bulbs out and putting them back in didn't make any difference. But the tungstens work unequivocally.

The puzzle for me is in what way LE bulbs respond differently from tungstens to variations in power supply.

The advice I have had from this thread tells me that this is not a commonly experienced problem, and that I need to test the whole system when I next visit. Then my daughter can pass the problem to the landlord.

 

[JohnD]

I would suspect worn lampholders, or weak springs. Bayonet holders often get loose where the slots in the ring are meant to grip the pins. If they are pendants this is very easy to fix, I'd suggest taking at least one up with you on your next visit. if that solves the problem, it'll be easy to do the rest.

Because CFLs are heavier than filament bulbs, they sometimes drag on the holder. This is especially a problem on battenholders or ceiling lamps where the bulb is not suspended vertically. I had this happen only yesterday on a bathroom ceiling enclosure where the lamp is held horizontally.

BTW, lampholders will last much longer in future as they will not get hot from the old filaments.

CFLs are so tolerant of supply variations that they last a lot longer where this happens. I spent some time in a small town in the US where overhead supplies and big electric heating systems made filament bulbs fail very early, and I was stunned that the local people insisted on buying cheap filament bulbs "because we get through so many"

 

[Manyanga]

Thanks John. Seems at least that the problem should not be caused by any intolerance of the LE bulbs, and may be something mechanical rather than electrical. It's easy enough for me to try changing one of the holders, and I should be able to give that a go next Sunday.

 

[Manyanga]

Just to sum up, the lighting turned out to be a less immediate concern. I took my LT7 to the house on Sunday and began by testing sockets on the ring main, and a radial spur that is taken directly from the fuse box - I can't call it a CU. Live to Neutral loop impedance was around .4 ohms, but Live to Earth gave readings of over 500 ohms. Among the disconnected and reconnected leads in the fuse box, there appears to be no effective earth. So the matter is now passed into the hands of a qualified electrician. Thanks for all the advice.