Can I ask advice, please. The bulb on my landing light, which is a two-way switch one with an with a switch down stairs and on the landing, ew recently and tripped the upstairs lighting circuit. As you only seem to be able to get LED lights now I replaced it with an LED equivalent to a 60W bulb.
Yesterday, the bedroom light and the landing light had only been on for about 20 minutes when the landing light blew again with quite a noise and a smell of burning. The metal bayonet part of the bulb was so hot you could hardly touch it.
Has anyone got any clue about this. Or should I just get an electrician in.
Thanks
Lawrie

On 11/02/2024 11:23, Lawrie Davidson wrote:
> Can I ask advice, please. The bulb on my landing light, which is a two-way switch one with an with a switch down stairs and on the landing, ew recently and tripped the upstairs lighting circuit. As you only seem to be able to get LED lights now I replaced it with an LED equivalent to a 60W bulb.
> Yesterday, the bedroom light and the landing light had only been on for about 20 minutes when the landing light blew again with quite a noise and a smell of burning. The metal bayonet part of the bulb was so hot you could hardly touch it.
> Has anyone got any clue about this. Or should I just get an electrician in.
> Thanks
> Lawrie
>

If you carry around an old style portable medium wave/long wave radio,
ie not DAB, do you get crackling interference reception in the vicinity?

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
<http://diverse.4mg.com/slr.htm>

On 11/02/2024 11:23, Lawrie Davidson wrote:
> Can I ask advice, please. The bulb on my landing light, which is a two-way switch one with an with a switch down stairs and on the landing, ew recently and tripped the upstairs lighting circuit. As you only seem to be able to get LED lights now I replaced it with an LED equivalent to a 60W bulb.
> Yesterday, the bedroom light and the landing light had only been on for about 20 minutes when the landing light blew again with quite a noise and a smell of burning. The metal bayonet part of the bulb was so hot you could hardly touch it.
> Has anyone got any clue about this. Or should I just get an electrician in.
> Thanks
> Lawrie

If the bulb has a glass shade it's probably due to the base of the LED
overheating. A LED, even though of much lower wattage, can overheat if
its base gets too hot as glass shades have no ventilation. This doesn't
affect old-style filament bulbs. Normally LEDs just fail without noise,
but it looks like something else happened.

--

Jeff

I'd be suspecting the actual socket arcing myself. It is really impossible
to get more volts at the socket than the mains uses unless some pretty
creative wiring is at play.
Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"N_Cook" <diverse@tcp.co.uk> wrote in message
news:uqaf9i$vhfs$1@dont-email.me...
> On 11/02/2024 11:23, Lawrie Davidson wrote:
>> Can I ask advice, please. The bulb on my landing light, which is a
>> two-way switch one with an with a switch down stairs and on the landing,
>> ew recently and tripped the upstairs lighting circuit. As you only seem
>> to be able to get LED lights now I replaced it with an LED equivalent to
>> a 60W bulb.
>> Yesterday, the bedroom light and the landing light had only been on for
>> about 20 minutes when the landing light blew again with quite a noise
>> and a smell of burning. The metal bayonet part of the bulb was so hot you
>> could hardly touch it.
>> Has anyone got any clue about this. Or should I just get an electrician
>> in.
>> Thanks
>> Lawrie
>>
>
> If you carry around an old style portable medium wave/long wave radio, ie
> not DAB, do you get crackling interference reception in the vicinity?
>
> --
> Global sea level rise to 2100 from curve-fitted existing altimetry data
> <http://diverse.4mg.com/slr.htm>

I am using CFLs in those globe shades since they seem to last almost for
ever., I think it was a little premature to stop making them as there are
some use cases where they work better than leds do. Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"Jeff Layman" <Jeff@invalid.invalid> wrote in message
news:uqafj9$vdjq$1@dont-email.me...
> On 11/02/2024 11:23, Lawrie Davidson wrote:
>> Can I ask advice, please. The bulb on my landing light, which is a
>> two-way switch one with an with a switch down stairs and on the landing,
>> ew recently and tripped the upstairs lighting circuit. As you only seem
>> to be able to get LED lights now I replaced it with an LED equivalent to
>> a 60W bulb.
>> Yesterday, the bedroom light and the landing light had only been on for
>> about 20 minutes when the landing light blew again with quite a noise
>> and a smell of burning. The metal bayonet part of the bulb was so hot you
>> could hardly touch it.
>> Has anyone got any clue about this. Or should I just get an electrician
>> in.
>> Thanks
>> Lawrie
>
> If the bulb has a glass shade it's probably due to the base of the LED
> overheating. A LED, even though of much lower wattage, can overheat if its
> base gets too hot as glass shades have no ventilation. This doesn't affect
> old-style filament bulbs. Normally LEDs just fail without noise, but it
> looks like something else happened.
>
> --
>
> Jeff
>

On Sun, 11 Feb 2024 03:23:24 -0800 (PST)
Lawrie Davidson <irisandlori@gmail.com> wrote:

> Can I ask advice, please. The bulb on my landing light, which is a
> two-way switch one with an with a switch down stairs and on the
> landing, ew recently and tripped the upstairs lighting circuit. As
> you only seem to be able to get LED lights now I replaced it with an
> LED equivalent to a 60W bulb. Yesterday, the bedroom light and the
> landing light had only been on for about 20 minutes when the landing
> light blew again with quite a noise and a smell of burning. The
> metal bayonet part of the bulb was so hot you could hardly touch it.
> Has anyone got any clue about this. Or should I just get an
> electrician in. Thanks Lawrie

When I read the Subject line, I thought it was a post about an airport
runway, or about an aircraft.

As you were.

--
Davey.

On 11/02/2024 11:23, Lawrie Davidson wrote:
> Can I ask advice, please. The bulb on my landing light, which is a
> two-way switch one with an with a switch down stairs and on the
> landing, ew recently and tripped the upstairs lighting circuit. As
> you only seem to be able to get LED lights now I replaced it with an
> LED equivalent to a 60W bulb. Yesterday, the bedroom light and the
> landing light had only been on for about 20 minutes when the landing
> light blew again with quite a noise and a smell of burning. The
> metal bayonet part of the bulb was so hot you could hardly touch it.
> Has anyone got any clue about this. Or should I just get an
> electrician in. Thanks Lawrie

You could just have been unlucky and got a duff bulb. I have had a LED
in the past where its base overheated from new - and failed after a few
hours.

You could also have a lose connection at the bulb holder, so I would be
wise to turn off the power and check that its screw connections are
good, and that the flex to it does not look burnt or discoloured.

--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

On 11/02/2024 12:46, Jeff Layman wrote:
> On 11/02/2024 11:23, Lawrie Davidson wrote:
>> Can I ask advice, please. The bulb on my landing light, which is a
>> two-way switch one with an with a switch down stairs and on the
>> landing, ew recently and tripped the upstairs lighting circuit. As you
>> only seem to be able to get LED lights now I replaced it with an LED
>> equivalent to a 60W bulb.
>> Yesterday, the bedroom light and the landing light had only been on
>> for about 20 minutes when the landing light blew again with quite a
>> noise and a smell of burning. The metal bayonet part of the bulb was
>> so hot you could hardly touch it.
>> Has anyone got any clue about this. Or should I just get an
>> electrician in.
>> Thanks
>> Lawrie
>
> If the bulb has a glass shade it's probably due to the base of the LED
> overheating. A LED, even though of much lower wattage, can overheat if
> its base gets too hot as glass shades have no ventilation. This doesn't
> affect old-style filament bulbs. Normally LEDs just fail without noise,
> but it looks like something else happened.
>

I would suspect a bad connection in the fitting and not necessary the bulb

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Sunday 11 February 2024 at 14:18:58 UTC, John Rumm wrote:
> On 11/02/2024 11:23, Lawrie Davidson wrote:
> > Can I ask advice, please. The bulb on my landing light, which is a
> > two-way switch one with an with a switch down stairs and on the
> > landing, ew recently and tripped the upstairs lighting circuit. As
> > you only seem to be able to get LED lights now I replaced it with an
> > LED equivalent to a 60W bulb. Yesterday, the bedroom light and the
> > landing light had only been on for about 20 minutes when the landing
> > light blew again with quite a noise and a smell of burning. The
> > metal bayonet part of the bulb was so hot you could hardly touch it.
> > Has anyone got any clue about this. Or should I just get an
> > electrician in. Thanks Lawrie
> You could just have been unlucky and got a duff bulb. I have had a LED
> in the past where its base overheated from new - and failed after a few
> hours.
>
> You could also have a lose connection at the bulb holder, so I would be
> wise to turn off the power and check that its screw connections are
> good, and that the flex to it does not look burnt or discoloured.

+1, and a loose arcing connection in the holder would most likely kill the LED bulb too. Could also be junk on the scket pins.
A simple diy job if you're capable.

On 11/02/2024 12:41, N_Cook wrote:
> On 11/02/2024 11:23, Lawrie Davidson wrote:
>> Can I ask advice, please. The bulb on my landing light, which is a
>> two-way switch one with an with a switch down stairs and on the
>> landing, ew recently and tripped the upstairs lighting circuit. As you
>> only seem to be able to get LED lights now I replaced it with an LED
>> equivalent to a 60W bulb.
>> Yesterday, the bedroom light and the landing light had only been on
>> for about 20 minutes when the landing light blew again with quite a
>> noise and a smell of burning. The metal bayonet part of the bulb was
>> so hot you could hardly touch it.
>> Has anyone got any clue about this. Or should I just get an
>> electrician in.
>> Thanks
>> Lawrie
>>
>
> If you carry around an old style portable medium wave/long wave radio,
> ie not DAB, do you get crackling interference reception in the vicinity?
>
Irrelevant.

BAD LED bulb blew its drivers. Probably the LEDS are fine but some
cheap chinesium capacitor has blown in it. Oddly enough I have had
slightly more failures in LED pendant hung bulbs than the candle ones
mounted base downwards.

Just buy another LED bulb from somewhere a bit better than the last one
- I actually found Homebase stocked a decent range - and write that one
off to experience.

'so hot you could hardly touch it' is the standard operating temperature
for most power semiconductors these days. which will fail at around
200°C internal temperature.

My Raspberry PI runs about 50°C and my old quad core CPU clocks in at
around 55°C.
Oddly this PC is reporting only 25°C but I am not sure I believe that.
When I used to design PA amplifiers the test was whether the power
transistors would hiss and turn a wet finger to steam. I tried to keep
them below 100°C.

I've had a diode unsolder itself it got so hot...and still work.

'so hot you could hardly touch it' is nothing at all to worry about.
--
"The most difficult subjects can be explained to the most slow witted
man if he has not formed any idea of them already; but the simplest
thing cannot be made clear to the most intelligent man if he is firmly
persuaded that he knows already, without a shadow of doubt, what is laid
before him."

- Leo Tolstoy

On 11/02/2024 12:46, Jeff Layman wrote:
> On 11/02/2024 11:23, Lawrie Davidson wrote:
>> Can I ask advice, please. The bulb on my landing light, which is a
>> two-way switch one with an with a switch down stairs and on the
>> landing, ew recently and tripped the upstairs lighting circuit. As you
>> only seem to be able to get LED lights now I replaced it with an LED
>> equivalent to a 60W bulb.
>> Yesterday, the bedroom light and the landing light had only been on
>> for about 20 minutes when the landing light blew again with quite a
>> noise and a smell of burning. The metal bayonet part of the bulb was
>> so hot you could hardly touch it.
>> Has anyone got any clue about this. Or should I just get an
>> electrician in.
>> Thanks
>> Lawrie
>
> If the bulb has a glass shade it's probably due to the base of the LED
> overheating. A LED, even though of much lower wattage, can overheat if
> its base gets too hot as glass shades have no ventilation. This doesn't
> affect old-style filament bulbs. Normally LEDs just fail without noise,
> but it looks like something else happened.
>
Bang and a Bad Smell is typical of a mains rated capacitor exploding.
It's probably fixable, but honestly, they are cheap enough.

--
“when things get difficult you just have to lie”

― Jean Claud Jüncker

On 11/02/2024 20:31, The Natural Philosopher wrote:

> BAD LED bulb blew its drivers. Probably the LEDS are fine but some
> cheap chinesium capacitor has blown in it. Oddly enough I have had
> slightly more failures in LED pendant hung bulbs than the candle ones
> mounted base downwards.

Why do you find that odd? The base contains the crappy electronics that
fail through heat, and when hung upside-down the base will get all the
trapped heat in a glass shade. I don't remember ever having a base-down
LED fail, but I've had more than a few "base-up" LEDs fail, in
particular G10s a few years ago (although newer ones are a lot better).

--

Jeff

On Mon, 12 Feb 2024 08:00:33 +0000
Jeff Layman <Jeff@invalid.invalid> wrote:

> On 11/02/2024 20:31, The Natural Philosopher wrote:
>
> > BAD LED bulb blew its drivers. Probably the LEDS are fine but some
> > cheap chinesium capacitor has blown in it. Oddly enough I have had
> > slightly more failures in LED pendant hung bulbs than the candle
> > ones mounted base downwards.
>
> Why do you find that odd? The base contains the crappy electronics
> that fail through heat, and when hung upside-down the base will get
> all the trapped heat in a glass shade. I don't remember ever having a
> base-down LED fail, but I've had more than a few "base-up" LEDs fail,
> in particular G10s a few years ago (although newer ones are a lot
> better).
>

The G10s have a humongous heatsink behind the LEDs, but there's an
outer plastic cover, so air circulation around the flared part needs to
be good. Some ceiling lampholders aren't too great for this, others are
very open.

--
Joe

Yes I once had a cfl fail as the heat glue and solder holding the lamp
melted and the tube fell on the floor. I took the bits back to B/Q and they
gave me another one with no such fault. I guess it is pretty cramped in
these bulbs to get the electronics inside. Another thing to look out for is
the cable from the rose to the bulb holder. They get hot with all the heat
and age and the insulation cracks and falls off.
I also remember when the early CFLs came out they were in a kind of jam jar
glass, and heavy as they had a choke inside. I had mor than one break the
lampholder bayonet and either fell to the floor or sagged at one side
creating arcing that blue the cut-out on the circuit. I don't know if your
LED was heavy, but lampholders do fail due to the heat of tungsten bulbs,
and it might be time for a new one and a new bit of cable.
Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"Animal" <tabbypurr@gmail.com> wrote in message
news:cbc87382-b74f-4041-9efa-deac87a9332bn@googlegroups.com...
> On Sunday 11 February 2024 at 14:18:58 UTC, John Rumm wrote:
>> On 11/02/2024 11:23, Lawrie Davidson wrote:
>> > Can I ask advice, please. The bulb on my landing light, which is a
>> > two-way switch one with an with a switch down stairs and on the
>> > landing, ew recently and tripped the upstairs lighting circuit. As
>> > you only seem to be able to get LED lights now I replaced it with an
>> > LED equivalent to a 60W bulb. Yesterday, the bedroom light and the
>> > landing light had only been on for about 20 minutes when the landing
>> > light blew again with quite a noise and a smell of burning. The
>> > metal bayonet part of the bulb was so hot you could hardly touch it.
>> > Has anyone got any clue about this. Or should I just get an
>> > electrician in. Thanks Lawrie
>> You could just have been unlucky and got a duff bulb. I have had a LED
>> in the past where its base overheated from new - and failed after a few
>> hours.
>>
>> You could also have a lose connection at the bulb holder, so I would be
>> wise to turn off the power and check that its screw connections are
>> good, and that the flex to it does not look burnt or discoloured.
>
> +1, and a loose arcing connection in the holder would most likely kill the
> LED bulb too. Could also be junk on the scket pins.
> A simple diy job if you're capable.

On 2/11/2024 6:23 AM, Lawrie Davidson wrote:
> Can I ask advice, please. The bulb on my landing light, which is a two-way switch one with an with a switch down stairs and on the landing, ew recently and tripped the upstairs lighting circuit. As you only seem to be able to get LED lights now I replaced it with an LED equivalent to a 60W bulb.
> Yesterday, the bedroom light and the landing light had only been on for about 20 minutes when the landing light blew again with quite a noise and a smell of burning. The metal bayonet part of the bulb was so hot you could hardly touch it.
> Has anyone got any clue about this. Or should I just get an electrician in.
> Thanks
> Lawrie
>

You should start by checking mains voltage to see
if there is anything abnormal about it.

If you do not own a meter, plug an incandescent bulb
into the socket and see if that is excessively bright,
indicating a too-high voltage.

This device, is an example of a metering circuit, without
needing to wave wires around while working. But it only
checks a wall outlet for the conditions it finds, such
as mains voltage. The computer I'm typing on, is connected
to one of these, so I can watch the power consumption.
But by pressing the voltage button, I can check the mains
voltage too.

https://en.wikipedia.org/wiki/Kill_A_Watt

The UK one has a volt button, just like mine does.

https://upload.wikimedia.org/wikipedia/commons/b/b7/Plug-in_Power_%26_Energy_Monitor_in_UK_Domestic_Mains_Socket.jpeg

The reason I'm looking at the voltage in the above answer,
is that it is unusual for a LED to blow in the first 20 minutes
of life, purely based on temperature. The electrolytic cap
in the base, could be a cap with a 2000 hour rating at 105C,
which is pretty hot. You might have to push it to 150C,
to get it to blow like that (take the 20 minutes to rise to
150C).

LED bulbs should not be operated inside sealed glass globes,
as then there isn't enough cooling air. The old incandescent bulbs,
they could take the heat, because of the materials they were
made of. Similarly, the socket for the incandescent bulb, is
designed for significant operating temperature. But LEDs
really do best, when there is free air circulating around them.
For semiconductor lasers, some of those "extinguish" their
optical output, at only 70C. LEDs are related to those.

I have some number of incandescent bulbs left, but they're for
test and not for regular usage. Incandescent bulbs are sensitive
to voltage, and if you don't have a meter handy, they're the next
best thing for a rough eyeball test that the voltage is normal.

LED bulbs are not sensitive to voltage, in the "intensity" sense.
If the voltage is 80% of normal, the LED bulb tries to glow
at the normal level. If the voltage is 120% of normal, the
LED bulb again tries to glow as normal. But the stress the
circuit is under, is definitely going to be different, if the
voltage is not the nominal value.

At 80% voltage, an incandescent is dim. At 120% voltage, it's
bright enough to indicate burn-out is imminent.

Say for example, you operated a LED lamp off the shaver outlet
in the bathroom. The LED lamp could blow instantly in there,
as the voltage on the shaver circuit can be higher than
nominal on a permanent basis. A lot of these electrical
goods (even including the Kill-a-Watt), do not list the
absolute max voltage they are rated to withstand. I don't
really know what a year 2023 or year 2024 LED bulb is rated
for, in terms of absolute max. Absolute max, is the voltage
that is guaranteed to kill an electrical good. Like my stereo
that went into the tip, it could not take voltage excursions
on mains, and mains is what killed my stereo. If you have
a mains problem, your stereo dying, is a sign of an abnormal
situation.

One way to get an abnormal voltage in a house, would be
if the house received more than one phase.

https://en.wikipedia.org/wiki/Three-phase_electric_power

"defining VLN as 100% gives VLL ≈ 100% × 1.73 = 173%" # Line to Line being not what you'd
# normally use in a lighting circuit.
# It's unlikely multiple phases would be
# present in the wiring though (LL for power
# instead of the normal LN).

Paul

Paul <nospam@needed.invalid> wrote
> Lawrie Davidson wrote

>> Can I ask advice, please. The bulb on my landing light, which is a
>> two-way switch one with an with a switch down stairs and on the
>> landing, ew recently and tripped the upstairs lighting circuit. As you
>> only seem to be able to get LED lights now I replaced it with an LED
>> equivalent to a 60W bulb.

>> Yesterday, the bedroom light and the landing light had only been on for
>> about 20 minutes when the landing light blew again with quite a noise
>> and a smell of burning. The metal bayonet part of the bulb was so hot
>> you could hardly touch it.

>> Has anyone got any clue about this. Or should I just get an
>> electrician in.

> You should start by checking mains voltageto see if there is anything
> abnormal about it.

Unlikely to be the problem with a led bulb.

> If you do not own a meter, plug an incandescentbulb into the socket and
> see if that is excessivelybright, indicating a too-high voltage.

> This device, is an example of a metering circuit, without
> needing to wave wires around while working. But it only
> checks a wall outlet for the conditions it finds, such
> as mains voltage. The computer I'm typing on, is connected
> to one of these, so I can watch the power consumption.
> But by pressing the voltage button, I can check the mains
> voltage too.

> https://en.wikipedia.org/wiki/Kill_A_Watt

> The UK one has a volt button, just like mine does.

> https://upload.wikimedia.org/wikipedia/commons/b/b7/Plug-in_Power_%26_Energy_Monitor_in_UK_Domestic_Mains_Socket.jpeg

> The reason I'm looking at the voltage in the above answer,
> is that it is unusual for a LED to blow in the first 20 minutes
> of life, purely based on temperature. The electrolytic cap
> in the base, could be a cap with a 2000 hour rating at 105C,
> which is pretty hot. You might have to push it to 150C, toget it to
> blow like that (take the 20 minutes to rise to 150C).

> LED bulbs should not be operated inside sealedglass globes, as then
> there isn't enough cooling air.

The filament leds work fine line that.

> The old incandescent bulbs, they could take the heat,because of the
> materials they were made of.

> Similarly, the socket for the incandescent bulb, is
> designed for significant operating temperature. But LEDs
> really do best, when there is free air circulating around them.

Depends on the bulb, the Philips Hue bulb run quite cool.

> For semiconductor lasers, some of those "extinguish"their optical
> output, at only 70C. LEDs are related to those.

> I have some number of incandescent bulbs left, but they're for
> test and not for regular usage. Incandescent bulbs are sensitive
> to voltage, and if you don't have a meter handy, they're the next
> best thing for a rough eyeball test that the voltage is normal.

> LED bulbs are not sensitive to voltage, in the "intensity"sense. If the
> voltage is 80% of normal, the LED bulb triesto glow at the normal
> level. If the voltage is 120% of normal,the LED bulb again tries to
> glow as normal. But the stressthe circuit is under, is definitely going
> to be different, if the
> voltage is not the nominal value.

A well designed led bulb should handle that fine.

> At 80% voltage, an incandescent is dim. At 120% voltage,it's bright
> enough to indicate burn-out is imminent.

> Say for example, you operated a LED lamp off the shaveroutlet in the
> bathroom. The LED lamp could blow instantlyin there, as the voltage on
> the shaver circuit can be higherthan nominal on a permanent basis. A
> lot of these electrical
> goods (even including the Kill-a-Watt), do not list the
> absolute max voltage they are rated to withstand. I don't
> really know what a year 2023 or year 2024 LED bulb is rated
> for, in terms of absolute max. Absolute max, is the voltage
> that is guaranteed to kill an electrical good. Like my stereo
> that went into the tip, it could not take voltage excursions
> on mains, and mains is what killed my stereo. If you have
> a mains problem, your stereo dying, is a sign of an abnormal
> situation.

> One way to get an abnormal voltage in a house,would be if the house
> received more than one phase.

Most UK houses don't.

> https://en.wikipedia.org/wiki/Three-phase_electric_power

> "defining VLN as 100% gives VLL ≈ 100% × 1.73 = 173%" # Line to
> Line being not what you'd
> # normally
> use in a lighting circuit.
> # It's
> unlikely multiple phases would be
> # present in
> the wiring though (LL for power
> # instead of
> the normal LN).

On Tue, 13 Feb 2024 08:06:23 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

<FLUSH the abnormal trolling senile cretin's latest trollshit unread>

--
Marland addressing senile Rodent's tall stories:
"Do you really think people believe your stories you come up with to boost
your self esteem."
Message-ID: <h88tt7FplhkU1@mid.individual.net>

On Monday 12 February 2024 at 20:41:36 UTC, Paul wrote:
> On 2/11/2024 6:23 AM, Lawrie Davidson wrote:
> > Can I ask advice, please. The bulb on my landing light, which is a two-way switch one with an with a switch down stairs and on the landing, ew recently and tripped the upstairs lighting circuit. As you only seem to be able to get LED lights now I replaced it with an LED equivalent to a 60W bulb.
> > Yesterday, the bedroom light and the landing light had only been on for about 20 minutes when the landing light blew again with quite a noise and a smell of burning. The metal bayonet part of the bulb was so hot you could hardly touch it.
> > Has anyone got any clue about this. Or should I just get an electrician in.
> > Thanks
> > Lawrie
> >
> You should start by checking mains voltage to see
> if there is anything abnormal about it.
>
> If you do not own a meter, plug an incandescent bulb
> into the socket and see if that is excessively bright,
> indicating a too-high voltage.
>
> This device, is an example of a metering circuit, without
> needing to wave wires around while working. But it only
> checks a wall outlet for the conditions it finds, such
> as mains voltage. The computer I'm typing on, is connected
> to one of these, so I can watch the power consumption.
> But by pressing the voltage button, I can check the mains
> voltage too.
>
> https://en.wikipedia.org/wiki/Kill_A_Watt
>
> The UK one has a volt button, just like mine does.
>
> https://upload.wikimedia.org/wikipedia/commons/b/b7/Plug-in_Power_%26_Energy_Monitor_in_UK_Domestic_Mains_Socket.jpeg
>
> The reason I'm looking at the voltage in the above answer,
> is that it is unusual for a LED to blow in the first 20 minutes
> of life, purely based on temperature. The electrolytic cap
> in the base, could be a cap with a 2000 hour rating at 105C,
> which is pretty hot. You might have to push it to 150C,
> to get it to blow like that (take the 20 minutes to rise to
> 150C).
>
> LED bulbs should not be operated inside sealed glass globes,
> as then there isn't enough cooling air. The old incandescent bulbs,
> they could take the heat, because of the materials they were
> made of. Similarly, the socket for the incandescent bulb, is
> designed for significant operating temperature. But LEDs
> really do best, when there is free air circulating around them.
> For semiconductor lasers, some of those "extinguish" their
> optical output, at only 70C. LEDs are related to those.
>
> I have some number of incandescent bulbs left, but they're for
> test and not for regular usage. Incandescent bulbs are sensitive
> to voltage, and if you don't have a meter handy, they're the next
> best thing for a rough eyeball test that the voltage is normal.
>
> LED bulbs are not sensitive to voltage, in the "intensity" sense.
> If the voltage is 80% of normal, the LED bulb tries to glow
> at the normal level. If the voltage is 120% of normal, the
> LED bulb again tries to glow as normal. But the stress the
> circuit is under, is definitely going to be different, if the
> voltage is not the nominal value.
>
> At 80% voltage, an incandescent is dim. At 120% voltage, it's
> bright enough to indicate burn-out is imminent.
>
> Say for example, you operated a LED lamp off the shaver outlet
> in the bathroom. The LED lamp could blow instantly in there,
> as the voltage on the shaver circuit can be higher than
> nominal on a permanent basis. A lot of these electrical
> goods (even including the Kill-a-Watt), do not list the
> absolute max voltage they are rated to withstand. I don't
> really know what a year 2023 or year 2024 LED bulb is rated
> for, in terms of absolute max. Absolute max, is the voltage
> that is guaranteed to kill an electrical good. Like my stereo
> that went into the tip, it could not take voltage excursions
> on mains, and mains is what killed my stereo. If you have
> a mains problem, your stereo dying, is a sign of an abnormal
> situation.

this is a nonissue in the uk.

> One way to get an abnormal voltage in a house, would be
> if the house received more than one phase.
>
> https://en.wikipedia.org/wiki/Three-phase_electric_power

so is that in > 99.9% of cases