From Newsgroup: uk.d-i-y

Hi All

I'm looking at getting some replacement light fittings and note that
they have a stated limit of 60 watts.

Does this only apply when the old incandescent type bulbs are to be used?
The LED bulbs display the equivalent old wattage e. g. 75w, but also
show the required power at 9.5w.
I expect that when the cooler operation LEDs are fitted, the 60 or 75w
value is no longer relevant.

Thanks

Phil
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From Newsgroup: uk.d-i-y

On 09/08/2026 16:23, Generalie wrote:

Hi All

I'm looking at getting some replacement light fittings and note that
they have a stated limit of 60 watts.

Does this only apply when the old incandescent type bulbs are to be used?
The LED bulbs display the equivalent old wattage e. g. 75w, but also
show the required power at 9.5w.
I expect that when the cooler operation LEDs are fitted, the 60 or 75w
value is no longer relevant.

Thanks

Phil

I can't work out from your post whether it's the new fittings or the old fittings that are limited to 60 or 75 watts. However, the new LED bulbs
will use less, so that's okay then.

Quite a lot of new LED fittings come with bulbs already fitted. These
usually can't be replaced.
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From Newsgroup: uk.d-i-y

On 09/08/2026 16:23, Generalie wrote:

Hi All

I'm looking at getting some replacement light fittings and note that
they have a stated limit of 60 watts.

Does this only apply when the old incandescent type bulbs are to be used?
The LED bulbs display the equivalent old wattage e. g. 75w, but also
show the required power at 9.5w.
I expect that when the cooler operation LEDs are fitted, the 60 or 75w
value is no longer relevant.

Thanks

Phil

Maybe the simpler answer was just "yes"?


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From Newsgroup: uk.d-i-y

In article <115a621$2e3s3$1@dont-email.me>,
Generalie <Generalie@nospam.com> wrote:

I'm looking at getting some replacement light fittings and note that
they have a stated limit of 60 watts.

Does this only apply when the old incandescent type bulbs are to be used?

The limit is because of the heat generated, which is the actual
wattage, not the "equivalent". No household LED bulb will approach
the limit.

-- Richard
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From Newsgroup: uk.d-i-y

Richard Tobin <richard@cogsci.ed.ac.uk> wrote:

In article <115a621$2e3s3$1@dont-email.me>,
Generalie <Generalie@nospam.com> wrote:

I'm looking at getting some replacement light fittings and note that
they have a stated limit of 60 watts.

Does this only apply when the old incandescent type bulbs are to be used?

The limit is because of the heat generated, which is the actual
wattage, not the "equivalent". No household LED bulb will approach
the limit.

Indeed, the rating is to do with the amount of heat you can emit before
melting / setting fire to the fitting.

Although LED bulbs in some fittings have been known to gradually cook themselves which shortens their life, well below the amount of heat needed
to damage the fitting. It's worth thinking about ventilation of the fitting
- eg an upturned bowl will collect the heat, whereas a cylindrical lampshade open at the top and bottom will allow fresh air to circulate to cool the
bulb.

Theo
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From Newsgroup: uk.d-i-y

In article <aWd*2GINA@news.chiark.greenend.org.uk>,
Theo <theom+news@chiark.greenend.org.uk> wrote:

Although LED bulbs in some fittings have been known to gradually cook >themselves which shortens their life, well below the amount of heat needed
to damage the fitting. It's worth thinking about ventilation of the fitting >- eg an upturned bowl will collect the heat, whereas a cylindrical lampshade >open at the top and bottom will allow fresh air to circulate to cool the >bulb.

I don't have any figures, but I'm doubtful about how significant this
is. I suspect that the internal temperature of the bulb depends more
on the design of the bulb itself than on the surrounding air flow.
Cheap bulbs are likely to lack enough metal to conduct the heat away
to the air.

-- Richard
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 09/08/2026 17:07, Richard Tobin wrote:

In article <aWd*2GINA@news.chiark.greenend.org.uk>,
Theo <theom+news@chiark.greenend.org.uk> wrote:

Although LED bulbs in some fittings have been known to gradually cook
themselves which shortens their life, well below the amount of heat needed >> to damage the fitting. It's worth thinking about ventilation of the fitting >> - eg an upturned bowl will collect the heat, whereas a cylindrical lampshade >> open at the top and bottom will allow fresh air to circulate to cool the
bulb.

I don't have any figures, but I'm doubtful about how significant this
is. I suspect that the internal temperature of the bulb depends more
on the design of the bulb itself than on the surrounding air flow.
Cheap bulbs are likely to lack enough metal to conduct the heat away
to the air.

Theo is right. I have some small ceiling lamps designed for G9 halogens.
They point down, but can be angled slightly as well, are made of glass,
and have no ventilation at the socket end. when I changed to G9 leds I
was surprised at how quickly those bulbs died. I assumed they
overheated, and tried a different make, but that also failed fairly quickly.

I eventually found that some Wilko 3.6W (33W halogen equivalent) lasted
well without dying. In fact, I have a couple of spares which I haven't
needed for 5+ years. Those bulbs are somewhat longer than the other G9s
and perhaps aren't so susceptible to the heat.
--
Jeff
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From Newsgroup: uk.d-i-y

Jeff Layman wrote:

I have some small ceiling lamps designed for G9 halogens. They point
down, but can be angled slightly as well, are made of glass, and have no ventilation at the socket end. when I changed to G9 leds I was surprised
at how quickly those bulbs died. I assumed they overheated, and tried a different make, but that also failed fairly quickly.

With incandescent and halogens, they produce 90-95% of their rated power
as infrared rather than visible light, which can escape somewhat.

LEDs tend to generate heat within the LED itself, so even if they are
lower actual power to begin with, 40-60% of that power ends up as heat,
with limited airflow for cooling, can tend to cook ...

--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 09/08/2026 16:23, Generalie wrote:

Hi All

I'm looking at getting some replacement light fittings and note that
they have a stated limit of 60 watts.

Does this only apply when the old incandescent type bulbs are to be used?

essentially yes

The LED bulbs display the equivalent old wattage e. g. 75w, but also
show the required power at 9.5w.
I expect that when the cooler operation LEDs are fitted, the 60 or 75w
value is no longer relevant.

You are correct

Thanks

Phil

--
All political activity makes complete sense once the proposition that
all government is basically a self-legalising protection racket, is
fully understood.


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From Newsgroup: uk.d-i-y

Andy Burns <usenet@andyburns.uk> wrote:

Jeff Layman wrote:

I have some small ceiling lamps designed for G9 halogens. They point
down, but can be angled slightly as well, are made of glass, and have no ventilation at the socket end. when I changed to G9 leds I was surprised at how quickly those bulbs died. I assumed they overheated, and tried a different make, but that also failed fairly quickly.

With incandescent and halogens, they produce 90-95% of their rated power
as infrared rather than visible light, which can escape somewhat.

LEDs tend to generate heat within the LED itself, so even if they are
lower actual power to begin with, 40-60% of that power ends up as heat,
with limited airflow for cooling, can tend to cook ...

Also a tungsten filament is by nature hot up to about 3000K. Semiconductor junctions are good to about 125C, but higher temperature causes faster
ageing, well below the tungsten temperature.

Persistently elevated temperatures can also damage other components like capacitors that are included as part of the lamp - if your capacitor dropper loses capacitance then it's not dropping so much voltage, you start to overvolt/overcurrent the LEDs, they run hotter, and conditions continue to deteriorate until something finally goes.

Theo
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From Newsgroup: uk.d-i-y

On 10/08/2026 00:04, Theo wrote:

Andy Burns <usenet@andyburns.uk> wrote:

Jeff Layman wrote:

I have some small ceiling lamps designed for G9 halogens. They point
down, but can be angled slightly as well, are made of glass, and have no >>> ventilation at the socket end. when I changed to G9 leds I was surprised >>> at how quickly those bulbs died. I assumed they overheated, and tried a
different make, but that also failed fairly quickly.

With incandescent and halogens, they produce 90-95% of their rated power
as infrared rather than visible light, which can escape somewhat.

LEDs tend to generate heat within the LED itself, so even if they are
lower actual power to begin with, 40-60% of that power ends up as heat,
with limited airflow for cooling, can tend to cook ...

Also a tungsten filament is by nature hot up to about 3000K. Semiconductor junctions are good to about 125C,

Nearer 180-#C these days

but higher temperature causes faster
ageing, well below the tungsten temperature.

Persistently elevated temperatures can also damage other components like capacitors that are included as part of the lamp - if your capacitor dropper loses capacitance then it's not dropping so much voltage, you start to overvolt/overcurrent the LEDs, they run hotter, and conditions continue to deteriorate until something finally goes.

Yes. I've had a lot of trouble with a room, used a lot, with a pair of
bulbs hanging down. LEDS keep popping even though the bulbs have plenty
of airflow.

other high use rooms have either 'candle' style bulbs or spotlight
bulbs. These seem to last better

Theo

--
"It is an established fact to 97% confidence limits that left wing conspirators see right wing conspiracies everywhere"

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From Newsgroup: uk.d-i-y

On 10 Aug 2026 at 00:04:06 BST, "Theo" <theom+news@chiark.greenend.org.uk> wrote:

Andy Burns <usenet@andyburns.uk> wrote:

Jeff Layman wrote:

I have some small ceiling lamps designed for G9 halogens. They point
down, but can be angled slightly as well, are made of glass, and have no >>> ventilation at the socket end. when I changed to G9 leds I was surprised >>> at how quickly those bulbs died. I assumed they overheated, and tried a
different make, but that also failed fairly quickly.

With incandescent and halogens, they produce 90-95% of their rated power
as infrared rather than visible light, which can escape somewhat.

LEDs tend to generate heat within the LED itself, so even if they are
lower actual power to begin with, 40-60% of that power ends up as heat,
with limited airflow for cooling, can tend to cook ...

Also a tungsten filament is by nature hot up to about 3000K. Semiconductor junctions are good to about 125C, but higher temperature causes faster ageing, well below the tungsten temperature.

Persistently elevated temperatures can also damage other components like capacitors that are included as part of the lamp - if your capacitor dropper loses capacitance then it's not dropping so much voltage, you start to overvolt/overcurrent the LEDs, they run hotter, and conditions continue to deteriorate until something finally goes.

Theo

Your technical description of the cause of events is not entirely correct (a fall in the capacitance of the dropper will lead to less current at the same voltage drop, making the light dimmer) but I don't disagree about the end result!
--

Roger Hayter
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From Newsgroup: uk.d-i-y

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other components like capacitors that are included as part of the lamp - if your capacitor
dropper loses capacitance then it's not dropping so much voltage, you
start to overvolt/overcurrent the LEDs, they run hotter, and conditions continue to deteriorate until something finally goes.

Capacitance dropping will underrun the leds.
--
braind
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From Newsgroup: uk.d-i-y

On Thu, 13 Aug 2026 01:57:56 +0100
me9 <me9@privacy.net> wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other components
like capacitors that are included as part of the lamp - if your
capacitor dropper loses capacitance then it's not dropping so much
voltage, you start to overvolt/overcurrent the LEDs, they run
hotter, and conditions continue to deteriorate until something
finally goes.

Capacitance dropping will underrun the leds.

There are two capacitors.
--
Joe

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From Newsgroup: uk.d-i-y

On 13 Aug 2026 at 10:43:33 BST, "Joe" <joe@jretrading.com> wrote:

On Thu, 13 Aug 2026 01:57:56 +0100
me9 <me9@privacy.net> wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other components
like capacitors that are included as part of the lamp - if your
capacitor dropper loses capacitance then it's not dropping so much
voltage, you start to overvolt/overcurrent the LEDs, they run
hotter, and conditions continue to deteriorate until something
finally goes.

Capacitance dropping will underrun the leds.

There are two capacitors.

Or maybe more. So - doesn't alter the statement that that reducing the voltage dropper capacitance will under run the LEDs.
--

Roger Hayter
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From Newsgroup: uk.d-i-y

On 14/08/2026 22:12, Roger Hayter wrote:

On 13 Aug 2026 at 10:43:33 BST, "Joe" <joe@jretrading.com> wrote:

On Thu, 13 Aug 2026 01:57:56 +0100
me9 <me9@privacy.net> wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other components
like capacitors that are included as part of the lamp - if your
capacitor dropper loses capacitance then it's not dropping so much
voltage, you start to overvolt/overcurrent the LEDs, they run
hotter, and conditions continue to deteriorate until something
finally goes.

Capacitance dropping will underrun the leds.

There are two capacitors.

Or maybe more. So - doesn't alter the statement that that reducing the voltage
dropper capacitance will under run the LEDs.

If you can find capacitor dropper LED bulbs BigClive has info here on
how to hack them, but as that page says LED bulb design has moved on.
Many , probably most, LEDs bulbs no longer use Capacitor Droppers as its
hard to achieve the required power factor. Instead they use multiple
LEDs in series to allow them to be driven at close to mains voltage,
with a constant current chip to keep the dissipation constant.

If you want to extend their like take a look at this "Big Clive" video
which I found interesting on how these work, why some are cheaper than
others and how to lower the dissipation...

https://www.youtube.com/watch?v=5HTa2jVi_rc

the data sheet for the current sense chip is here

https://www.scribd.com/document/717381518/SM2082D-datasheet

Dave
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From Newsgroup: uk.d-i-y

On 14 Aug 2026 21:12:31 GMT
Roger Hayter <roger@hayter.org> wrote:

On 13 Aug 2026 at 10:43:33 BST, "Joe" <joe@jretrading.com> wrote:

On Thu, 13 Aug 2026 01:57:56 +0100
me9 <me9@privacy.net> wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other
components like capacitors that are included as part of the lamp
- if your capacitor dropper loses capacitance then it's not
dropping so much voltage, you start to overvolt/overcurrent the
LEDs, they run hotter, and conditions continue to deteriorate
until something finally goes.

Capacitance dropping will underrun the leds.

There are two capacitors.

Or maybe more. So - doesn't alter the statement that that reducing
the voltage dropper capacitance will under run the LEDs.

And reducing the larger value capacitor in the dropper will *increase*
the LED drive.

It works pretty much like a resistive voltage divider if the current
drawn is small, remembering that the larger the capacitor, the smaller
the reactance.
--
Joe

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On 15 Aug 2026 at 11:45:40 BST, "Joe" <joe@jretrading.com> wrote:

On 14 Aug 2026 21:12:31 GMT
Roger Hayter <roger@hayter.org> wrote:

On 13 Aug 2026 at 10:43:33 BST, "Joe" <joe@jretrading.com> wrote:

On Thu, 13 Aug 2026 01:57:56 +0100
me9 <me9@privacy.net> wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other
components like capacitors that are included as part of the lamp
- if your capacitor dropper loses capacitance then it's not
dropping so much voltage, you start to overvolt/overcurrent the
LEDs, they run hotter, and conditions continue to deteriorate
until something finally goes.

Capacitance dropping will underrun the leds.

There are two capacitors.

Or maybe more. So - doesn't alter the statement that that reducing
the voltage dropper capacitance will under run the LEDs.

And reducing the larger value capacitor in the dropper will *increase*
the LED drive.

It works pretty much like a resistive voltage divider if the current
drawn is small, remembering that the larger the capacitor, the smaller
the reactance.

No it doesn't. The voltage across the LED is largely governed by the
properties of the LED, and putting a large capacitor across it might vary the reactive current but doesn't act as a voltage divider at all.
--

Roger Hayter
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From Newsgroup: uk.d-i-y

On 15/08/2026 13:45, Roger Hayter wrote:

On 15 Aug 2026 at 11:45:40 BST, "Joe" <joe@jretrading.com> wrote:

On 14 Aug 2026 21:12:31 GMT
Roger Hayter <roger@hayter.org> wrote:

On 13 Aug 2026 at 10:43:33 BST, "Joe" <joe@jretrading.com> wrote:

On Thu, 13 Aug 2026 01:57:56 +0100
me9 <me9@privacy.net> wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other
components like capacitors that are included as part of the lamp
- if your capacitor dropper loses capacitance then it's not
dropping so much voltage, you start to overvolt/overcurrent the
LEDs, they run hotter, and conditions continue to deteriorate
until something finally goes.

Capacitance dropping will underrun the leds.

There are two capacitors.

Or maybe more. So - doesn't alter the statement that that reducing
the voltage dropper capacitance will under run the LEDs.

And reducing the larger value capacitor in the dropper will *increase*
the LED drive.

It works pretty much like a resistive voltage divider if the current
drawn is small, remembering that the larger the capacitor, the smaller
the reactance.

No it doesn't. The voltage across the LED is largely governed by the properties of the LED, and putting a large capacitor across it might vary the reactive current but doesn't act as a voltage divider at all.

The problem is that once you introduce a non linear element like an LED
you can essentially throw all of the linear analyses out of the window.

A large part of circuit design consits in arranging things so you dont
have to deal with that.
--
"Women actually are capable of being far more than the feminists will
let them."



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From Newsgroup: uk.d-i-y

On 15 Aug 2026 at 14:06:44 BST, "The Natural Philosopher"
<tnp@invalid.invalid> wrote:

On 15/08/2026 13:45, Roger Hayter wrote:

On 15 Aug 2026 at 11:45:40 BST, "Joe" <joe@jretrading.com> wrote:

On 14 Aug 2026 21:12:31 GMT
Roger Hayter <roger@hayter.org> wrote:

On 13 Aug 2026 at 10:43:33 BST, "Joe" <joe@jretrading.com> wrote:

On Thu, 13 Aug 2026 01:57:56 +0100
me9 <me9@privacy.net> wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other
components like capacitors that are included as part of the lamp >>>>>>> - if your capacitor dropper loses capacitance then it's not
dropping so much voltage, you start to overvolt/overcurrent the
LEDs, they run hotter, and conditions continue to deteriorate
until something finally goes.

Capacitance dropping will underrun the leds.

There are two capacitors.

Or maybe more. So - doesn't alter the statement that that reducing
the voltage dropper capacitance will under run the LEDs.

And reducing the larger value capacitor in the dropper will *increase*
the LED drive.

It works pretty much like a resistive voltage divider if the current
drawn is small, remembering that the larger the capacitor, the smaller
the reactance.

No it doesn't. The voltage across the LED is largely governed by the
properties of the LED, and putting a large capacitor across it might vary the
reactive current but doesn't act as a voltage divider at all.

The problem is that once you introduce a non linear element like an LED
you can essentially throw all of the linear analyses out of the window.

A large part of circuit design consits in arranging things so you dont
have to deal with that.

For instance by setting bounds within which linear approximations are valid.
--

Roger Hayter
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On 15/08/2026 15:56, Roger Hayter wrote:

On 15 Aug 2026 at 14:06:44 BST, "The Natural Philosopher" <tnp@invalid.invalid> wrote:

On 15/08/2026 13:45, Roger Hayter wrote:

On 15 Aug 2026 at 11:45:40 BST, "Joe" <joe@jretrading.com> wrote:

On 14 Aug 2026 21:12:31 GMT
Roger Hayter <roger@hayter.org> wrote:

On 13 Aug 2026 at 10:43:33 BST, "Joe" <joe@jretrading.com> wrote:

On Thu, 13 Aug 2026 01:57:56 +0100
me9 <me9@privacy.net> wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Persistently elevated temperatures can also damage other
components like capacitors that are included as part of the lamp >>>>>>>> - if your capacitor dropper loses capacitance then it's not
dropping so much voltage, you start to overvolt/overcurrent the >>>>>>>> LEDs, they run hotter, and conditions continue to deteriorate
until something finally goes.

Capacitance dropping will underrun the leds.

There are two capacitors.

Or maybe more. So - doesn't alter the statement that that reducing
the voltage dropper capacitance will under run the LEDs.

And reducing the larger value capacitor in the dropper will *increase* >>>> the LED drive.

It works pretty much like a resistive voltage divider if the current
drawn is small, remembering that the larger the capacitor, the smaller >>>> the reactance.

No it doesn't. The voltage across the LED is largely governed by the
properties of the LED, and putting a large capacitor across it might vary the
reactive current but doesn't act as a voltage divider at all.

The problem is that once you introduce a non linear element like an LED
you can essentially throw all of the linear analyses out of the window.

A large part of circuit design consits in arranging things so you dont
have to deal with that.

For instance by setting bounds within which linear approximations are valid.

Exactly...
And using parts which have linear characteristics to compensate for
those that do not
--
The New Left are the people they warned you about.

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