I have one of these ...
http://www.tlc-direct.co.uk/Products/GULEDW.html

.... fitted into one of these in my shower ...
http://www.screwfix.com/app/sfd/cat/...13995&id=16012

It's kind of weird, certainly in terms of the light it gives out. But
what has me a bit worried is the fact that the LEDs stay dimly
illuminated even when the pull-cord switch is off! I had GU10 bulb
fitted before which certainly went off when it was supposed to. So
what's going on? Is this a sign of some serious electrical fault??

Whoops, the light fitting is in fact the 240v model:
http://www.screwfix.com/app/sfd/cat/...48434&ts=15222

Martin Pentreath wrote:
Whoops, the light fitting is in fact the 240v model:
http://www.screwfix.com/app/sfd/cat/...48434&ts=15222

It's a similar effect to the commonly asked 'why do my CF bulbs flash
when off'.

There is a very small capacitance formed between the wires of cables.
This capacitance, lets the AC voltage 'leak' through between wires,
and induce a small current.
It's utterly harmless (unless the cables are kilometers long), and
pretty much happens because current design practices for house wiring
were designed for filliment bulbs, where this level of current causes
them to warm to a couple of C over ambient.
With many sorts of energy saving light, this can instead produce very
small amounts of light, instead.

The amount of light needed to be visible in a dark room is very, very
small.
A normal LED torch runs at 20 thousandths of an amp.
At a millionth of an amp, it's clearly visible in a dark room.

Thanks Ian, I can shower with confidence again!

Ian Stirling wrote:

There is a very small capacitance formed between the wires of cables.
This capacitance, lets the AC voltage 'leak' through between wires,
and induce a small current.
It's utterly harmless (unless the cables are kilometers long), and
pretty much happens because current design practices for house wiring
were designed for filliment bulbs, where this level of current causes
them to warm to a couple of C over ambient.
With many sorts of energy saving light, this can instead produce very
small amounts of light, instead.

Another thing to check that can make this effect more prononunced is if
the switch is in the neutral rather than the live...

--
Cheers,

John.

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Another thing to check that can make this effect more prononunced is if
the switch is in the neutral rather than the live...

And also those light switches that have an indicator that comes on when the
main light is off to show you where the switch is. These rely on a small
leakage current through the bulb to light the neon and are only suitable for
filament bulbs.

Christian.

On Mon, 3 Apr 2006 10:52:24 UTC, "Christian McArdle"
wrote:

Another thing to check that can make this effect more prononunced is if
the switch is in the neutral rather than the live...

And also those light switches that have an indicator that comes on when the
main light is off to show you where the switch is. These rely on a small
leakage current through the bulb to light the neon and are only suitable for
filament bulbs.

Actually, we have one of those for the hall light. The switch in
question is just inside the front door, and it's a useful place to have
an illuminated switch.

But there are no filament bulbs on the circuit - just two CFLs (OK, in
parallel, of course) and there seems to be enough leakage to make it
work.

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