On 01/01/2020 14:54, Scott wrote:
So all appliances are designed to be safe with a 13 amp fuse?

Generally yes - for some value of 'safe' in that many appliances will
self destruct and go open circuit before the fuse goes.

On Wed, 1 Jan 2020 15:50:44 +0000, Mike Clarke
wrote:

On 01/01/2020 14:54, Scott wrote:
So all appliances are designed to be safe with a 13 amp fuse?

Generally yes - for some value of 'safe' in that many appliances will
self destruct and go open circuit before the fuse goes.

Interesting. I assume that is why charging units do not have a fuse.

However, we keep being told that the fuse is to protect the flex. If
a fault develops in the flex the appliance might not be involved.

On Wednesday, 1 January 2020 12:40:59 UTC, Dave Plowman (News) wrote:
In article ,
Scott wrote:

When the ring main system was introduced (in 1947, I believe), the
correct fuse was used for each appliance. Why have we moved away from
this commonsense arrangement and apparently degraded a safety feature?

Because to know what the correct size fuse is, you'd need to know the
cable size. Somewhat easier with removable plugs, but guesswork with
moulded types.

And perhaps most only want to get the thing working again, so will fit any
fuse they have to hand, or can buy easily. Most likely 13 amp.

The correct fuse doesn't depend on cable size at all, it depends on the load ie the appliance.


NT

On Wednesday, 1 January 2020 14:08:52 UTC, Scott wrote:
On Wed, 1 Jan 2020 05:21:54 -0800 (PST),
wrote:
On Monday, 30 December 2019 22:12:42 UTC, tabby wrote:

Leads were often very thin, basically what we now call speaker wire.
Using under 3A fuses is wise if such wire is used.

Leads were also longer as people had fewer sockets. Remember the days you'd get a good 2 or 3 yards of flex on a table lamp.

Now all EU appliances are supposed to be okay with unfused plugs as that's normal in Europe, and leads are shorter to provide less resistance so a higher rated fuse/MCB blows quickly enough.

Lucky Golden Hedgehog leads from China are still on the thin side though.

If the purpose of the fuse is to protect the flex (as is often said),
does this mean all flexes can cope with 16 amps (European radial
circuit)?

No.


NT

On Wednesday, 1 January 2020 14:39:48 UTC, Mike Clarke wrote:
On 01/01/2020 13:07, Scott wrote:

Okay, but any sensible person would replace like for like. You could
say the same about 3A fuses.

That works on the assumption that most people are sensible.

There are many who would happily keep trying the next larger size fuse
until it 'worked'.

and sometimes that is a sensible option. If your appliance has had its 13A fuse replaced with a 2A and it blows on occasion, trying a 3A is a fair thing to do by someone that doesn't understand what fuse to choose.


NT

On Wednesday, 1 January 2020 14:54:33 UTC, Scott wrote:
On Wed, 1 Jan 2020 14:39:45 +0000, Mike Clarke
wrote:
On 01/01/2020 13:07, Scott wrote:

Okay, but any sensible person would replace like for like. You could
say the same about 3A fuses.

That works on the assumption that most people are sensible.

There are many who would happily keep trying the next larger size fuse
until it 'worked'.

So all appliances are designed to be safe with a 13 amp fuse? The

no, though it's often said. Most is though.

flex on the lamp I bought from John Lewis does not look to me that it
could carry 13 amps but I could be wrong. I won't be trying it out.

It can, as I found out, but not really safely.


NT

On Wednesday, 1 January 2020 16:36:54 UTC, Scott wrote:
On Wed, 1 Jan 2020 15:50:44 +0000, Mike Clarke
wrote:
On 01/01/2020 14:54, Scott wrote:

So all appliances are designed to be safe with a 13 amp fuse?

Generally yes - for some value of 'safe' in that many appliances will
self destruct and go open circuit before the fuse goes.

Interesting. I assume that is why charging units do not have a fuse.

However, we keep being told that the fuse is to protect the flex.

We are told that. IRL it protects the appliance as well. There is a lot of oversimplification out there. Fuses may be simple devices, but fusing is a nontrivial subject, and attempting to simplify it here is not going to result in a proper understanding. If you want to know it all, find the relevant materials & read.


NT

On Wed, 1 Jan 2020 14:39:51 -0800 (PST), wrote:

On Wednesday, 1 January 2020 14:08:52 UTC, Scott wrote:
On Wed, 1 Jan 2020 05:21:54 -0800 (PST),
wrote:
On Monday, 30 December 2019 22:12:42 UTC, tabby wrote:

Leads were often very thin, basically what we now call speaker wire.
Using under 3A fuses is wise if such wire is used.

Leads were also longer as people had fewer sockets. Remember the days you'd get a good 2 or 3 yards of flex on a table lamp.

Now all EU appliances are supposed to be okay with unfused plugs as that's normal in Europe, and leads are shorter to provide less resistance so a higher rated fuse/MCB blows quickly enough.

Lucky Golden Hedgehog leads from China are still on the thin side though.

If the purpose of the fuse is to protect the flex (as is often said),
does this mean all flexes can cope with 16 amps (European radial
circuit)?

No.

Thanks. I'll stick with my plan of reassessing the fuses and fitting
the one I think is appropriate for the appliance involved (never
higher than the original of course). .

On Wednesday, 1 January 2020 14:08:52 UTC, Scott wrote:
If the purpose of the fuse is to protect the flex (as is often said),
does this mean all flexes can cope with 16 amps (European radial
circuit)?

In theory yes (for new appliances), as the short-circuit current should be high enough to blow the circuit fuse before flashbangenpoppen occur.

Personally I think it's a nasty continental habit.

Owain

On 02/01/2020 11:25, wrote:
On Wednesday, 1 January 2020 14:08:52 UTC, Scott wrote:
If the purpose of the fuse is to protect the flex (as is often said),
does this mean all flexes can cope with 16 amps (European radial
circuit)?

In theory yes (for new appliances), as the short-circuit current should be high enough to blow the circuit fuse before flashbangenpoppen occur.

Personally I think it's a nasty continental habit.


I don't see anything nasty in having to check only the consumer unit
rather than both the consumer unit and the fuse when faced with a
aufgehortarbeitensituation.

And cartridge fuses are soooo ungreen.


--
Robin
reply-to address is (intended to be) valid

On Thu, 2 Jan 2020 11:58:01 +0000, Robin wrote:

On 02/01/2020 11:25, wrote:
On Wednesday, 1 January 2020 14:08:52 UTC, Scott wrote:
If the purpose of the fuse is to protect the flex (as is often said),
does this mean all flexes can cope with 16 amps (European radial
circuit)?

In theory yes (for new appliances), as the short-circuit current should be high enough to blow the circuit fuse before flashbangenpoppen occur.

Personally I think it's a nasty continental habit.


I don't see anything nasty in having to check only the consumer unit
rather than both the consumer unit and the fuse when faced with a
aufgehortarbeitensituation.

With a ring main this would be 32A. I don't fancy blasting that size
of current through a faulty domestic appliance.

And cartridge fuses are soooo ungreen.

I could probably count on one hand the ones that have failed in the
last decade. Fires are more ungreen, as the Aussies are discovering.

On Monday, 30 December 2019 22:14:50 UTC, wrote:
On Monday, 30 December 2019 11:01:02 UTC, Scott wrote:
On Sun, 29 Dec 2019 23:41:59 +0000, Steve Walker

IIRC the IEC plugs commonly used on computer, hi-fi, entertainment
systems, even (hot version) kettles these days, are only rated for 10A.
As they may be swapped between devices, it'd make sense to make them all
rated 10A and use a 10A fuse.

I noticed that with two computer cables both fused at 10A. I replaced
the printer with 5A (claimed rating 2.5A). I don't know what to use
for the PC itself because of the array of components involved.
Thinking about 7A :-)

PCs typically take an amp or less. Only high power systems eat more. While '500w' PSUs are moderately common, they're normally not 500w, and a computer that eats 500w is an unusual animal. Hype rules.

I think the new Mac Pro towers have 1.4Kw PSUs




NT

On Thursday, 2 January 2020 11:25:20 UTC, wrote:
On Wednesday, 1 January 2020 14:08:52 UTC, Scott wrote:
If the purpose of the fuse is to protect the flex (as is often said),
does this mean all flexes can cope with 16 amps (European radial
circuit)?

In theory yes (for new appliances), as the short-circuit current should be high enough to blow the circuit fuse before flashbangenpoppen occur.

that doesn't make them 16A rated

On Thursday, 2 January 2020 16:25:29 UTC, whisky-dave wrote:
On Monday, 30 December 2019 22:14:50 UTC, tabby wrote:
On Monday, 30 December 2019 11:01:02 UTC, Scott wrote:
On Sun, 29 Dec 2019 23:41:59 +0000, Steve Walker

IIRC the IEC plugs commonly used on computer, hi-fi, entertainment
systems, even (hot version) kettles these days, are only rated for 10A.
As they may be swapped between devices, it'd make sense to make them all
rated 10A and use a 10A fuse.

I noticed that with two computer cables both fused at 10A. I replaced
the printer with 5A (claimed rating 2.5A). I don't know what to use
for the PC itself because of the array of components involved.
Thinking about 7A :-)

PCs typically take an amp or less. Only high power systems eat more. While '500w' PSUs are moderately common, they're normally not 500w, and a computer that eats 500w is an unusual animal. Hype rules.

I think the new Mac Pro towers have 1.4Kw PSUs

whatever for? They're not PCS anyway.

wrote:

whisky-dave wrote:

I think the new Mac Pro towers have 1.4Kw PSUs

whatever for?

28 core xeon CPU = 300W
12x 128GB RAM = (maybe?) 550W
Vega Pro II GPU = 475W

On Thursday, 2 January 2020 21:37:48 UTC, Andy Burns wrote:
tabbypurr wrote:
whisky-dave wrote:

I think the new Mac Pro towers have 1.4Kw PSUs

whatever for?

28 core xeon CPU = 300W
12x 128GB RAM = (maybe?) 550W
Vega Pro II GPU = 475W

a long way from a normal PC then.

On 02/01/2020 22:49, wrote:
On Thursday, 2 January 2020 21:37:48 UTC, Andy Burns wrote:
tabbypurr wrote:
whisky-dave wrote:

I think the new Mac Pro towers have 1.4Kw PSUs

whatever for?

28 core xeon CPU = 300W
12x 128GB RAM = (maybe?) 550W
Vega Pro II GPU = 475W

a long way from a normal PC then.


Okay, a fairly typical example of a slightly older PC with a highish end
(for the time) processor and a medium range (?) graphics card (the one
my three sons had until a recent upgrade:

CPU: AMD FX-8350 (not overclocked)
Memory: 2 x 8GB DDR3
Video: NVidia GeForce GTX 1050 Ti
Storage: 2 x SSD, 2 x SATA III 7200rpm HDD
PCIe cards: Single port Ethernet, DVB-T Tuner
Keyboard: Gaming keyboard
Mouse: Gaming mouse
USB devices: Hub, external HDD, Sometimes a couple of Arduinos
Other devices: Integral card reader
Fans: 4 x 120mm
Usage: 8 hours per day, 4 of it gaming

Using an online power requirements calculator, that gives a load of 424W
and recommended a PSU of at least 474W.

Adding a second graphics card in SLI mode (as huge numbers of gamer do)
would bump it up enough for a 650W to 700W PSU to be required.

SteveW

On Thursday, 2 January 2020 23:39:45 UTC, Steve Walker wrote:
On 02/01/2020 22:49, tabbypurr wrote:
On Thursday, 2 January 2020 21:37:48 UTC, Andy Burns wrote:
tabbypurr wrote:
whisky-dave wrote:

I think the new Mac Pro towers have 1.4Kw PSUs

whatever for?

28 core xeon CPU = 300W
12x 128GB RAM = (maybe?) 550W
Vega Pro II GPU = 475W

a long way from a normal PC then.


Okay, a fairly typical example of a slightly older PC with a highish end
(for the time) processor and a medium range (?) graphics card (the one
my three sons had until a recent upgrade:

CPU: AMD FX-8350 (not overclocked)
Memory: 2 x 8GB DDR3
Video: NVidia GeForce GTX 1050 Ti
Storage: 2 x SSD, 2 x SATA III 7200rpm HDD
PCIe cards: Single port Ethernet, DVB-T Tuner
Keyboard: Gaming keyboard
Mouse: Gaming mouse
USB devices: Hub, external HDD, Sometimes a couple of Arduinos
Other devices: Integral card reader
Fans: 4 x 120mm
Usage: 8 hours per day, 4 of it gaming

Using an online power requirements calculator, that gives a load of 424W
and recommended a PSU of at least 474W.

Adding a second graphics card in SLI mode (as huge numbers of gamer do)
would bump it up enough for a 650W to 700W PSU to be required.

SteveW

With respect for an old pc 16G ram, 4 hdds/ssds, 2 arduinos, 4 fans is a long way from a typical pc. Bit pointless isn't it.

In article ,
wrote:
And perhaps most only want to get the thing working again, so will fit
any fuse they have to hand, or can buy easily. Most likely 13 amp.

The correct fuse doesn't depend on cable size at all, it depends on the
load ie the appliance.

********. The fuse in a plug is only there to protect the cable. If the
appliance needs a fuse it will be in or on it.

--
*Why do the two "sanction"s (noun and verb) mean opposites?*

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 03 Jan 2020 14:26:51 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
wrote:
And perhaps most only want to get the thing working again, so will fit
any fuse they have to hand, or can buy easily. Most likely 13 amp.

The correct fuse doesn't depend on cable size at all, it depends on the
load ie the appliance.

********. The fuse in a plug is only there to protect the cable. If the
appliance needs a fuse it will be in or on it.

What appliances do not need a fuse?

On Friday, 3 January 2020 16:15:15 UTC, Scott wrote:
On Fri, 03 Jan 2020 14:26:51 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
wrote:
And perhaps most only want to get the thing working again, so will fit
any fuse they have to hand, or can buy easily. Most likely 13 amp.

The correct fuse doesn't depend on cable size at all, it depends on the
load ie the appliance.

********. The fuse in a plug is only there to protect the cable. If the
appliance needs a fuse it will be in or on it.

What appliances do not need a fuse?

Aga cooker. Gas ascots. My electric toothbrush doesn;t have a fuse, and niether does the charging station (that I know of) the 2 pin plug goes into an atapter
which does have a 3 amp fuse in it IIRC, same as with my shaver.

But I guess it does depend on what you mean by an appliance, and whether that
includes what powers the appliance(s)

On Fri, 3 Jan 2020 08:39:25 -0800 (PST), whisky-dave
wrote:

On Friday, 3 January 2020 16:15:15 UTC, Scott wrote:
On Fri, 03 Jan 2020 14:26:51 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
wrote:
And perhaps most only want to get the thing working again, so will fit
any fuse they have to hand, or can buy easily. Most likely 13 amp.

The correct fuse doesn't depend on cable size at all, it depends on the
load ie the appliance.

********. The fuse in a plug is only there to protect the cable. If the
appliance needs a fuse it will be in or on it.

What appliances do not need a fuse?

Aga cooker. Gas ascots. My electric toothbrush doesn;t have a fuse, and niether does the charging station (that I know of) the 2 pin plug goes into an atapter
which does have a 3 amp fuse in it IIRC, same as with my shaver.

Are you sure the charging station doesn't have some form of internal
fuse? What happens if it is plugged into a 16 amp 'continental'
supply? I think shaver adapters contain a 1 amp fuse.

But I guess it does depend on what you mean by an appliance, and whether that
includes what powers the appliance(s)

I was responding to Mr Plowman. I'll adopt his definition.

In article ,
whisky-dave wrote:
********. The fuse in a plug is only there to protect the cable. If
the appliance needs a fuse it will be in or on it.

What appliances do not need a fuse?

Aga cooker. Gas ascots. My electric toothbrush doesn;t have a fuse, and
niether does the charging station (that I know of) the 2 pin plug goes
into an atapter which does have a 3 amp fuse in it IIRC, same as with my
shaver.

Things with a transformer (that might catch fire) often have a thermal
fuse in the windings. Non replaceable.

Relying on a plug fuse would be plain daft. All too easy to fit the wrong
one.

A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

--
*It's this dirty because I washed it with your wife's knickers*

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 03 Jan 2020 19:34:33 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
whisky-dave wrote:
********. The fuse in a plug is only there to protect the cable. If
the appliance needs a fuse it will be in or on it.

What appliances do not need a fuse?

Aga cooker. Gas ascots. My electric toothbrush doesn;t have a fuse, and
niether does the charging station (that I know of) the 2 pin plug goes
into an atapter which does have a 3 amp fuse in it IIRC, same as with my
shaver.

Things with a transformer (that might catch fire) often have a thermal
fuse in the windings. Non replaceable.

Relying on a plug fuse would be plain daft. All too easy to fit the wrong
one.

A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

Actually some plugs carry a sticker saying 'Fitted with 3 Amp fuse'.

On Friday, 3 January 2020 14:36:02 UTC, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
And perhaps most only want to get the thing working again, so will fit
any fuse they have to hand, or can buy easily. Most likely 13 amp.

The correct fuse doesn't depend on cable size at all, it depends on the
load ie the appliance.

********. The fuse in a plug is only there to protect the cable. If the
appliance needs a fuse it will be in or on it.

Start by doing some reading. You'll soon find yourself in posession of a clue.

On Friday, 3 January 2020 19:36:07 UTC, Dave Plowman (News) wrote:

Things with a transformer (that might catch fire) often have a thermal
fuse in the windings. Non replaceable.

often yes. And often no.

Relying on a plug fuse would be plain daft. All too easy to fit the wrong
one.

That you think it daft makes zero difference to the fact that that is how it was done for a long time, and old appliances have not in most cases sprouted an extra fuse since construction.

A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

No. It was reckoned that people could normally work out for themselves that a radio should be on a 2A plug, and a toaster on a 15A, which have since morphed into a 3A fuse & a 13A fuse in the square pin plug. Today we know that often people don't know this stuff.


NT

On Fri, 3 Jan 2020 12:54:55 -0800 (PST), wrote:

On Friday, 3 January 2020 19:36:07 UTC, Dave Plowman (News) wrote:

Things with a transformer (that might catch fire) often have a thermal
fuse in the windings. Non replaceable.

often yes. And often no.

Relying on a plug fuse would be plain daft. All too easy to fit the wrong
one.

That you think it daft makes zero difference to the fact that that is how it was done for a long time, and old appliances have not in most cases sprouted an extra fuse since construction.

A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

No. It was reckoned that people could normally work out for themselves that a radio should be on a 2A plug, and a toaster on a 15A, which have since morphed into a 3A fuse & a 13A fuse in the square pin plug. Today we know that often people don't know this stuff.

My toaster only needs a 7A fuse. I think 2A would suffice for a radio
(though not a TV).

On 03/01/2020 04:42, wrote:
On Thursday, 2 January 2020 23:39:45 UTC, Steve Walker wrote:
On 02/01/2020 22:49, tabbypurr wrote:
On Thursday, 2 January 2020 21:37:48 UTC, Andy Burns wrote:
tabbypurr wrote:
whisky-dave wrote:

I think the new Mac Pro towers have 1.4Kw PSUs

whatever for?

28 core xeon CPU = 300W
12x 128GB RAM = (maybe?) 550W
Vega Pro II GPU = 475W

a long way from a normal PC then.


Okay, a fairly typical example of a slightly older PC with a highish end
(for the time) processor and a medium range (?) graphics card (the one
my three sons had until a recent upgrade:

CPU: AMD FX-8350 (not overclocked)
Memory: 2 x 8GB DDR3
Video: NVidia GeForce GTX 1050 Ti
Storage: 2 x SSD, 2 x SATA III 7200rpm HDD
PCIe cards: Single port Ethernet, DVB-T Tuner
Keyboard: Gaming keyboard
Mouse: Gaming mouse
USB devices: Hub, external HDD, Sometimes a couple of Arduinos
Other devices: Integral card reader
Fans: 4 x 120mm
Usage: 8 hours per day, 4 of it gaming

Using an online power requirements calculator, that gives a load of 424W
and recommended a PSU of at least 474W.

Adding a second graphics card in SLI mode (as huge numbers of gamer do)
would bump it up enough for a 650W to 700W PSU to be required.

SteveW

With respect for an old pc 16G ram, 4 hdds/ssds, 2 arduinos, 4 fans is a long way from a typical pc. Bit pointless isn't it.

If you are only going to be running Office or similar and browsing the
Web, yes. But most children and many adults game, which pushes machines
much harder and those with a specific interest in computers and not just
using them as a basic tool, often run many things at once.

When running multiple programs, more RAM means less paging to hard-disk.
16G is not at all an unusual figure and the difference in performance is
noticeable under load. RAM sticks are preferably installed in pairs to
maximise performance and two 8Gb sticks take pretty well the same power
as two 4Gb or even two 2Gb sticks.

There were 2 x SSDs to allow one to be dedicated to Windows, while the
other had various different OSs installed at different times. The
hard-disks were to provide larger amounts of temporary local storage and
prior to the SSDs were the only storage on the machine. Until recently,
the cost of SSDs was high enough to make using one without an additional
hdd unaffordable for a main machine.

The Arduinos are a tiny part of the load and only happened to be there
as my eldest son was experimenting with Arduinos and Ethernet.

4 fans is not unusual, many cases come with multiple fans as standard.
In this case, there was an inlet, outlet and 2 x CPU cooler fans.
Multiple fans running slowly move as much air, while being a lot quieter
than single fans running faster. The reason for the 2 x CPU cooler fans
was simply that the cooler had the facility for two, we had a spare and
fitting it made the CPU run noticeably cooler ... which of course
prolongs its life - especially with a son who spent time experimenting
with overclocking.

That is pretty immaterial though - the big loads on any system are the
processor, motherboard and graphics card - none of which were unusual
and were all chosen on a price/performance basis, so as to give the best
useful lifetime for a reasonable cost. Indeed, although the machine has
been upgraded to a Ryzen 5 based one, the motherboard, CPU and RAM are
now moved to another machine and will be used for some years yet - my
middle son's machine was using an Intel Q6600 before that and had become
painfully slow!

SteveW

On Monday, December 30, 2019 at 1:48:01 AM UTC+11, Mike Clarke wrote:
On 29/12/2019 13:01, Scott wrote:

I appreciate that the fuse is intended to protect the lead not the
appliance, but surely there is a side-effect of protecting the
appliance? Is there any benefit in fitting a fuse significantly
larger than needed? Common sense suggests go for maximum protection.

In the event of an internal fault in an appliance containing electronics
then the chances are that one of the components will release its smoke
and permanently disable the appliance much faster than the 'correctly'
rated fuse would blow. So not much point in trying to protect anything
except the lead.

But.. but ..there are normal, and fast blowing fuses. One should think before changing !

"Scott" wrote in message
...
On Fri, 03 Jan 2020 14:26:51 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
wrote:
And perhaps most only want to get the thing working again, so will fit
any fuse they have to hand, or can buy easily. Most likely 13 amp.

The correct fuse doesn't depend on cable size at all, it depends on the
load ie the appliance.

********. The fuse in a plug is only there to protect the cable. If the
appliance needs a fuse it will be in or on it.

What appliances do not need a fuse?

Kettles, toasters, convection ovens, irons etc etc etc.

On Sat, 4 Jan 2020 13:41:58 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


What appliances do not need a fuse?

Kettles, toasters, convection ovens, irons etc etc etc.

And the senile bull****ting continues! tsk


--
addressing nym-shifting senile Rodent:
"You on the other hand are a heavyweight bull****ter who demonstrates
your particular prowess at it every day."
MID:

In article ,
Scott wrote:
A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

Actually some plugs carry a sticker saying 'Fitted with 3 Amp fuse'.

A sticker, yes. Not likely to survive long.

--
*Gaffer tape - The Force, light and dark sides - holds the universe together*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
wrote:
On Friday, 3 January 2020 19:36:07 UTC, Dave Plowman (News) wrote:

Things with a transformer (that might catch fire) often have a thermal
fuse in the windings. Non replaceable.

often yes. And often no.

Relying on a plug fuse would be plain daft. All too easy to fit the
wrong one.

That you think it daft makes zero difference to the fact that that is
how it was done for a long time, and old appliances have not in most
cases sprouted an extra fuse since construction.

And long experience is why their aren't lots of values now used.

A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

No. It was reckoned that people could normally work out for themselves
that a radio should be on a 2A plug, and a toaster on a 15A, which have
since morphed into a 3A fuse & a 13A fuse in the square pin plug. Today
we know that often people don't know this stuff.

2 amp plug? Does that restrict the peak current to 2 amps?

In the days of radial 5 and 15 amp circuits, the fuse was in the CU. And a
15 amp socket would often have an adaptor. With no fuse.


NT

--
*How does Moses make his tea? Hebrews it.*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Scott wrote:
My toaster only needs a 7A fuse. I think 2A would suffice for a radio
(though not a TV).

Early colour TVs could have a high inrush current enough to blow a 13 amp
fuse, even when the quoted power consumption was well below 3kW. But not
the anti-surge type fitted to the TV.

--
*Frustration is trying to find your glasses without your glasses.

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 04 Jan 2020 13:35:07 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
wrote:
On Friday, 3 January 2020 19:36:07 UTC, Dave Plowman (News) wrote:

Things with a transformer (that might catch fire) often have a thermal
fuse in the windings. Non replaceable.

often yes. And often no.

Relying on a plug fuse would be plain daft. All too easy to fit the
wrong one.

That you think it daft makes zero difference to the fact that that is
how it was done for a long time, and old appliances have not in most
cases sprouted an extra fuse since construction.

And long experience is why their aren't lots of values now used.

A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

No. It was reckoned that people could normally work out for themselves
that a radio should be on a 2A plug, and a toaster on a 15A, which have
since morphed into a 3A fuse & a 13A fuse in the square pin plug. Today
we know that often people don't know this stuff.

2 amp plug? Does that restrict the peak current to 2 amps?

In the days of radial 5 and 15 amp circuits, the fuse was in the CU. And a
15 amp socket would often have an adaptor. With no fuse.

Interesting question: were the 15 amp sockets and 5 amp sockets on
different circuits or mixed together?

On Saturday, 4 January 2020 13:36:11 UTC, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Friday, 3 January 2020 19:36:07 UTC, Dave Plowman (News) wrote:

Things with a transformer (that might catch fire) often have a thermal
fuse in the windings. Non replaceable.

often yes. And often no.

Relying on a plug fuse would be plain daft. All too easy to fit the
wrong one.

That you think it daft makes zero difference to the fact that that is
how it was done for a long time, and old appliances have not in most
cases sprouted an extra fuse since construction.

And long experience is why their aren't lots of values now used.

but there are lots of values in use

A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

No. It was reckoned that people could normally work out for themselves
that a radio should be on a 2A plug, and a toaster on a 15A, which have
since morphed into a 3A fuse & a 13A fuse in the square pin plug. Today
we know that often people don't know this stuff.

2 amp plug? Does that restrict the peak current to 2 amps?

do you know anything at all about this topic?

In the days of radial 5 and 15 amp circuits, the fuse was in the CU. And a
15 amp socket would often have an adaptor. With no fuse.

2A circuits too.


NT

On Saturday, 4 January 2020 15:52:22 UTC, Scott wrote:
On Sat, 04 Jan 2020 13:35:07 +0000 (GMT), "Dave Plowman (News)"
wrote:
In article ,
tabbypurr wrote:
On Friday, 3 January 2020 19:36:07 UTC, Dave Plowman (News) wrote:

Things with a transformer (that might catch fire) often have a thermal
fuse in the windings. Non replaceable.

often yes. And often no.

Relying on a plug fuse would be plain daft. All too easy to fit the
wrong one.

That you think it daft makes zero difference to the fact that that is
how it was done for a long time, and old appliances have not in most
cases sprouted an extra fuse since construction.

And long experience is why their aren't lots of values now used.

A fuse on say a radio etc that can be replaced has the correct type
printed beside it. No such thing on a plug.

No. It was reckoned that people could normally work out for themselves
that a radio should be on a 2A plug, and a toaster on a 15A, which have
since morphed into a 3A fuse & a 13A fuse in the square pin plug. Today
we know that often people don't know this stuff.

2 amp plug? Does that restrict the peak current to 2 amps?

In the days of radial 5 and 15 amp circuits, the fuse was in the CU. And a
15 amp socket would often have an adaptor. With no fuse.

Interesting question: were the 15 amp sockets and 5 amp sockets on
different circuits or mixed together?

In practice it wasn't unusual to find 5A sockets on a 15A fuse. Best practice wasn't followed to the degree it is today.


NT

On 04/01/2020 13:35, Dave Plowman (News) wrote:
In the days of radial 5 and 15 amp circuits, the fuse was in the CU. And a
15 amp socket would often have an adaptor. With no fuse.

And most people were blissfully unaware of things like current rating.
Back in the 1950s we happily ran a 2Kw electric fire off a 5A 2 pin
socket - it was the only socket in the room.

On Sunday, 5 January 2020 10:25:10 UTC, Mike Clarke wrote:
On 04/01/2020 13:35, Dave Plowman (News) wrote:

In the days of radial 5 and 15 amp circuits, the fuse was in the CU. And a
15 amp socket would often have an adaptor. With no fuse.

And most people were blissfully unaware of things like current rating.
Back in the 1950s we happily ran a 2Kw electric fire off a 5A 2 pin
socket - it was the only socket in the room.

I think people were less concerned, as well as many didn't understand the 2/5/15A system. A lot of things were normal then that would have many people wet themselves with fear today. People ran 1 bar fires off BC sockets.


NT

On Friday, 3 January 2020 17:36:34 UTC, Scott wrote:
On Fri, 3 Jan 2020 08:39:25 -0800 (PST), whisky-dave
wrote:

On Friday, 3 January 2020 16:15:15 UTC, Scott wrote:
On Fri, 03 Jan 2020 14:26:51 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
wrote:
And perhaps most only want to get the thing working again, so will fit
any fuse they have to hand, or can buy easily. Most likely 13 amp.

The correct fuse doesn't depend on cable size at all, it depends on the
load ie the appliance.

********. The fuse in a plug is only there to protect the cable. If the
appliance needs a fuse it will be in or on it.

What appliances do not need a fuse?

Aga cooker. Gas ascots. My electric toothbrush doesn't have a fuse, and niether does the charging station (that I know of) the 2 pin plug goes into an atapter
which does have a 3 amp fuse in it IIRC, same as with my shaver.

Are you sure the charging station doesn't have some form of internal
fuse?

I assume it does but we are talking about appliancies where the fuse can be replaced. AFAIK my toothbrush does NOT contain a fuse.
The charging station should have a fuse as that is the ONLY section connected to the mains supply and in accordence with UK electrical safety must contain some sort of fuse, whether it is current or temperature driven,
resetable or not I don't know, but it is most likely a non-servicable pat the
a user shouldn't replace.

The statement was what appliances NEED a fuse and not whether they have one or not, there is a differnce there too.





What happens if it is plugged into a 16 amp 'continental'
supply?

I doubt it'll fit. The toothbrush just has a rechraging receptical
that using induction for charging.

I think shaver adapters contain a 1 amp fuse.
Some do others don't. My toothbrush was NOT supplied with one.



But I guess it does depend on what you mean by an appliance, and whether that
includes what powers the appliance(s)

I was responding to Mr Plowman. I'll adopt his definition.