I was surprised to see 5-Amp round-pin sockets in a relatively new
hotel in England (The Village Hotel in Walsall).

When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

Thanks (in advance) for satisfying my idle curiosity.

pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes of
a vacuum cleaner into it - a 5amp socket fits the bill.

"Harry Bloomfield" wrote in message
news
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to use
an uncommon plug and socket, to avoid someone plugging the likes of a
vacuum cleaner into it - a 5amp socket fits the bill.

So does this circumstance qualify as an exemption from the normal rules
(building regs?) that only square-pin sockets must be used?

I know that plugs in hard-to-reach places such as theatre lights high above
a stage are allowed to use round-pin plugs because these do not have a fuse,
so there's no chance of an inaccessible fuse blowing during a performance. I
remember when I did the lighting for a school play being told that, and
shown where the fuse-wire fuses for each circuit were placed: right above
the fader for that light, so easy to reach in the semi-dark to replace if it
happens mid-performance. There was a stack of pre-wired fuses available in
case it happened. Obviously if the replacement fuse blows too, you give up!

On 01/07/2017 20:14, Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes of
a vacuum cleaner into it - a 5amp socket fits the bill.

Yes. When I built our conservatory, I fitted conventional 13A sockets
for power and 5A, round-pin ones for additional lighting. So the 3-gang
light switch switches ceiling lights; wall lights; and 5A sockets. We
only normally use the 5A sockets for Christmas lights.

SteveW

"Steve Walker" wrote in message
news
On 01/07/2017 20:14, Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes of a
vacuum cleaner into it - a 5amp socket fits the bill.

Yes. When I built our conservatory, I fitted conventional 13A sockets for
power and 5A, round-pin ones for additional lighting. So the 3-gang light
switch switches ceiling lights; wall lights; and 5A sockets. We only
normally use the 5A sockets for Christmas lights.


I've not seen table lamps switched by a common wall switch in this country,
but they were very common in the USA when I visited my sister while she was
living there. And in that case they used normal power sockets which
presumably were rated at the normal current for a socket in 120V-land.

Harry Bloomfield wrote:

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes of
a vacuum cleaner into it - a 5amp socket fits the bill.

Thanks Harry. That makes sense.
My idle curiosity has been satisfied.

Pete

In article , NY
wrote:
"Steve Walker" wrote in message
news
On 01/07/2017 20:14, Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with both 5-
and 15-Amp round-pin plugs, but understood that they were
obsolescent, and all new construction and remodel jobs used the new
13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction? Are they used
for a specific purpose (these were for bedside lights)?

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes
of a vacuum cleaner into it - a 5amp socket fits the bill.

Yes. When I built our conservatory, I fitted conventional 13A sockets
for power and 5A, round-pin ones for additional lighting. So the
3-gang light switch switches ceiling lights; wall lights; and 5A
sockets. We only normally use the 5A sockets for Christmas lights.


I've not seen table lamps switched by a common wall switch in this
country,

Parents' house built about 1900 had this.

--
from KT24 in Surrey, England

Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes
of a vacuum cleaner into it - a 5amp socket fits the bill.

It's far more likely in order to deter guests from taking the bedside lamps
home with them.

Yes the plug could be changed but most people who thieve from hotels
wouldn't know that.

On 01/07/2017 20:43, NY wrote:
"Steve Walker" wrote in message
news
On 01/07/2017 20:14, Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual
to use an uncommon plug and socket, to avoid someone plugging the
likes of a vacuum cleaner into it - a 5amp socket fits the bill.

Yes. When I built our conservatory, I fitted conventional 13A sockets
for power and 5A, round-pin ones for additional lighting. So the
3-gang light switch switches ceiling lights; wall lights; and 5A
sockets. We only normally use the 5A sockets for Christmas lights.


I've not seen table lamps switched by a common wall switch in this
country, but they were very common in the USA when I visited my sister
while she was living there. And in that case they used normal power
sockets which presumably were rated at the normal current for a socket
in 120V-land.

It's just a convenience thing - no switching off the light from the
doorway and then realising that you need to put it back on, go over to
the table lamp, Christmas tree, etc. and switch each off and then turn
the main light off again. Also means that at Christmas, we can turn the
tree lights, fairy lights over the top of the window and lights on the
wreath at the door on and later off with a single switch.

SteveW

Harry Bloomfield wrote:
To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes of
a vacuum cleaner into it - a 5amp socket fits the bill.

It's also possible to attach a dimmer to that circuit so that a table lamp
can be dimmed from a remote switch. Prevents someone attaching their phone
charger to the circuit and it getting all confused by the choppy waveform.

(is there a modern way to do remote LED dimming these days, eg some kind of
signal from the remote switch, or do they still do old-fashioned triac
waveform chopping? Obviously there's some kind of RF signalling, but
wondered if there's a standard protocol for wired lights)

Theo

On Saturday, 1 July 2017 21:07:25 UTC+1, Theo wrote:
(is there a modern way to do remote LED dimming these days, eg some kind of
signal from the remote switch, or do they still do old-fashioned triac
waveform chopping?

Various proprietary and open systems, including DALI

https://en.wikipedia.org/wiki/Digita...ting_Interface

Owain

On Saturday, 1 July 2017 20:37:20 UTC+1, Steve Walker wrote:
Yes. When I built our conservatory, I fitted conventional 13A sockets
for power and 5A, round-pin ones for additional lighting. So the 3-gang
light switch switches ceiling lights; wall lights; and 5A sockets. We
only normally use the 5A sockets for Christmas lights.

I've got 4 x 5A sockets in the lounge for table lamps; they're on the 2 walls that don't have wall lights.

8 light switches in the lounge.

Owain

In article ,
"NY" writes:
"Harry Bloomfield" wrote in message
news
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to use
an uncommon plug and socket, to avoid someone plugging the likes of a
vacuum cleaner into it - a 5amp socket fits the bill.

So does this circumstance qualify as an exemption from the normal rules
(building regs?) that only square-pin sockets must be used?

There is no such rule.
BS546 (round pin plugs and sockets) is still a current standard.
If you use them in domestic premises, it is now required that
you use versions with shuttered sockets.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Saturday, 1 July 2017 22:45:14 UTC+1, Andrew Gabriel wrote:
In article ,
"NY" writes:
"Harry Bloomfield" wrote in message
news
pfraser brought next idea :

When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to use
an uncommon plug and socket, to avoid someone plugging the likes of a
vacuum cleaner into it - a 5amp socket fits the bill.

So does this circumstance qualify as an exemption from the normal rules
(building regs?) that only square-pin sockets must be used?

There is no such rule.
BS546 (round pin plugs and sockets) is still a current standard.
If you use them in domestic premises, it is now required that
you use versions with shuttered sockets.

But I don't think BS372 are permitted.


NT

On Sat, 1 Jul 2017 20:43:22 +0100
"NY" wrote:

"Steve Walker" wrote in message
news
On 01/07/2017 20:14, Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is
usual to use an uncommon plug and socket, to avoid someone
plugging the likes of a vacuum cleaner into it - a 5amp socket
fits the bill.

Yes. When I built our conservatory, I fitted conventional 13A
sockets for power and 5A, round-pin ones for additional lighting.
So the 3-gang light switch switches ceiling lights; wall lights;
and 5A sockets. We only normally use the 5A sockets for Christmas
lights.


I've not seen table lamps switched by a common wall switch in this
country, but they were very common in the USA when I visited my
sister while she was living there. And in that case they used normal
power sockets which presumably were rated at the normal current for a
socket in 120V-land.


Agreed, from my years of living there. Very confusing the first time
you try to get the standard lamp working, as there is no suggestion
that it is controlled by a wall switch as well as its own switch.
Hotels also confused by doing the same thing, and included the TV set in
this mass switch-off. It then had to be re-programmed every time the
room was entered, but this thankfully got better as the sets began to
have memory built in.

--
Davey.

On Saturday, 1 July 2017 20:43:29 UTC+1, NY wrote:
"Steve Walker" wrote in message
news
On 01/07/2017 20:14, Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes of a
vacuum cleaner into it - a 5amp socket fits the bill.

Yes. When I built our conservatory, I fitted conventional 13A sockets for
power and 5A, round-pin ones for additional lighting. So the 3-gang light
switch switches ceiling lights; wall lights; and 5A sockets. We only
normally use the 5A sockets for Christmas lights.


I've not seen table lamps switched by a common wall switch in this country,
but they were very common in the USA when I visited my sister while she was
living there. And in that case they used normal power sockets which
presumably were rated at the normal current for a socket in 120V-land.

It's common for anyone thatwants it.
I have them myself for table lamps..

On Sunday, 2 July 2017 00:28:45 UTC+1, wrote:
But I don't think BS372 are permitted.

My school science labs were originally wired with them. They'd been repurposed into ELV supply for ripple tank lamps and similar.

BS 4573 plugs are.

See also
http://cpc.farnell.com/mk/k700whi/sh...olt/dp/PL00575

Owain

"NY" wrote in message
o.uk...
"Steve Walker" wrote in message
news
On 01/07/2017 20:14, Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes of
a vacuum cleaner into it - a 5amp socket fits the bill.

Yes. When I built our conservatory, I fitted conventional 13A sockets for
power and 5A, round-pin ones for additional lighting. So the 3-gang light
switch switches ceiling lights; wall lights; and 5A sockets. We only
normally use the 5A sockets for Christmas lights.


I've not seen table lamps switched by a common wall switch in this
country, but they were very common in the USA

Standard build in Sweden where in many houses they will be the only form of
room lighting.

what's really annoying is that there will often (only) be a socket at the
top of a wall to plug the light into and a hook in the centre of the room to
hang it on, so you have to drape a cable 12 foot across the ceiling between
them.

and what's more, the standard purchase option for room lamps is with
pre-installed 1 metre cables, so you have to unpick it all and DIY to
actually get a lamp in the centre of the room (****s).

tim

Not sure, but I too have seen some with shrouded pins just like the big ones
with rectangular pins and a teeny 5 amp fuse inside.
Maybe in reality it does not matter as long as its safe.

After all you seem to find all sorts of strange multi plug devices about
nowadays with iec type plugs like thos on the back of computers, and I am
not sure those are really supposed to be used in trailing sockets as the
plugs have no fuses at all!
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"pfraser" wrote in message
news
I was surprised to see 5-Amp round-pin sockets in a relatively new
hotel in England (The Village Hotel in Walsall).

When I lived in the UK (up until 1981) I was familiar with
both 5- and 15-Amp round-pin plugs, but understood that they
were obsolescent, and all new construction and remodel jobs
used the new 13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

Thanks (in advance) for satisfying my idle curiosity.

In article ,
pfraser wrote:
Why are there round-pin plugs used in new construction?
Are they used for a specific purpose (these were for
bedside lights)?

You have it in one.

If that circuit had say a dimmer, and had a normal 13 amp outlet, there is
the possibility of plugging in say a fan heater and blowing up the dimmer.

--
*You can't have everything, where would you put it?*

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

In article ,
NY wrote:
I've not seen table lamps switched by a common wall switch in this
country,

I've got several here. But fed from a dimmer on the same panel as other
lights.

--
*Elephants are the only mammals that can't jump *

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

In article ,
Phil L wrote:
To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes
of a vacuum cleaner into it - a 5amp socket fits the bill.

It's far more likely in order to deter guests from taking the bedside
lamps home with them.

You need to be a lot more careful of your guests.

--
*A conscience is what hurts when all your other parts feel so good *

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

tim... wrote:



Standard build in Sweden where in many houses they will be the only form of
room lighting.

what's really annoying is that there will often (only) be a socket at the
top of a wall to plug the light into and a hook in the centre of the room to
hang it on, so you have to drape a cable 12 foot across the ceiling between
them.

and what's more, the standard purchase option for room lamps is with
pre-installed 1 metre cables, so you have to unpick it all and DIY to
actually get a lamp in the centre of the room (****s).

tim


Were the hooks originally intended for oil lamps?

--

Roger Hayter

After serious thinking Brian Gaff wrote :
Not sure, but I too have seen some with shrouded pins just like the big ones
with rectangular pins and a teeny 5 amp fuse inside.
Maybe in reality it does not matter as long as its safe.

No need to fuse it down, if the supply circuit is already of a suitable
rating.

There was an hospital plug system, where a round pin plug/socket was
used which had a screw in fuse as the live pin, maximum 13amps. The
sockets were wired as per a normal 30amp ring main circuit, but using a
different style of fused plug.

It detered people from stealing the appliances and people plugging
normal rectangular 13amp plugs into the hospitals supplies.

On 01/07/17 20:57, charles wrote:
In article , NY
wrote:
"Steve Walker" wrote in message
news
On 01/07/2017 20:14, Harry Bloomfield wrote:
pfraser brought next idea :
When I lived in the UK (up until 1981) I was familiar with both 5-
and 15-Amp round-pin plugs, but understood that they were
obsolescent, and all new construction and remodel jobs used the new
13-Amp rectangular-pin sockets.

Why are there round-pin plugs used in new construction? Are they used
for a specific purpose (these were for bedside lights)?

To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes
of a vacuum cleaner into it - a 5amp socket fits the bill.

Yes. When I built our conservatory, I fitted conventional 13A sockets
for power and 5A, round-pin ones for additional lighting. So the
3-gang light switch switches ceiling lights; wall lights; and 5A
sockets. We only normally use the 5A sockets for Christmas lights.


I've not seen table lamps switched by a common wall switch in this
country,

Parents' house built about 1900 had this.


I'm pretty sure a relative who had a house built to his specification
has some sockets which are like that. The lighting (and other
'electrics' are computer controlled. There are several small switch pads
in each room and you can control most, if not all, the light etc in the
room from them. Some have remote control. All a bit complicated if you
are a visitor ;-)

It all works very well and is quite impressive but he did comment that
the system was already obsolete (it was installed 15+ years ago) and,
if anything failed, he may have issues replacing modules. I was curious
how it was configured but didn't get the opportunity to discuss it in
detail.

On Sun, 02 Jul 2017 12:53:36 +0100, Harry Bloomfield
wrote:

After serious thinking Brian Gaff wrote :
Not sure, but I too have seen some with shrouded pins just like the big ones
with rectangular pins and a teeny 5 amp fuse inside.
Maybe in reality it does not matter as long as its safe.

No need to fuse it down, if the supply circuit is already of a suitable
rating.

There was an hospital plug system, where a round pin plug/socket was
used which had a screw in fuse as the live pin, maximum 13amps. The
sockets were wired as per a normal 30amp ring main circuit, but using a
different style of fused plug.

Sounds like a Dorman & Smith style plug.

It detered people from stealing the appliances and people plugging
normal rectangular 13amp plugs into the hospitals supplies.

It's also got a nasty design fault. If the fuse comes out of the plug
when it's removed from the socket, you've got a live metal pin
sticking out.

In article ,
Harry Bloomfield wrote:
After serious thinking Brian Gaff wrote :
Not sure, but I too have seen some with shrouded pins just like the big
ones with rectangular pins and a teeny 5 amp fuse inside.
Maybe in reality it does not matter as long as its safe.

No need to fuse it down, if the supply circuit is already of a suitable
rating.

But if it's a lighting circuit it may only be capable of 6A.

There was an hospital plug system, where a round pin plug/socket was
used which had a screw in fuse as the live pin, maximum 13amps. The
sockets were wired as per a normal 30amp ring main circuit, but using a
different style of fused plug.

It detered people from stealing the appliances and people plugging
normal rectangular 13amp plugs into the hospitals supplies.

Those were made by D&S. A contender for the ring main system (there were
others). Some blocks of flats in central London used them and you could buy
spare fuses in Selfridges! BBC TV Centre also used them for technical
supplies until somebody discovered that you could leave the fused leg in
the socket when removing the plug.

--
from KT24 in Surrey, England

"Roger Hayter" wrote in message
...
tim... wrote:



Standard build in Sweden where in many houses they will be the only form
of
room lighting.

what's really annoying is that there will often (only) be a socket at the
top of a wall to plug the light into and a hook in the centre of the room
to
hang it on, so you have to drape a cable 12 foot across the ceiling
between
them.

and what's more, the standard purchase option for room lamps is with
pre-installed 1 metre cables, so you have to unpick it all and DIY to
actually get a lamp in the centre of the room (****s).

tim


Were the hooks originally intended for oil lamps?

in a new build apartment

I doubt it



--

Roger Hayter

In article ,
Harry Bloomfield wrote:
There was an hospital plug system, where a round pin plug/socket was
used which had a screw in fuse as the live pin, maximum 13amps. The
sockets were wired as per a normal 30amp ring main circuit, but using a
different style of fused plug.

It detered people from stealing the appliances

Not really as those D&S plugs were used in some domestic premises.


and people plugging
normal rectangular 13amp plugs into the hospitals supplies.

is a more likely reason. The BBC used those horrid D&S plugs for technical
mains.

--
*Never put off until tomorrow what you can avoid altogether *

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

In article ,
Caecilius wrote:
Sounds like a Dorman & Smith style plug.

Yup.

It detered people from stealing the appliances and people plugging
normal rectangular 13amp plugs into the hospitals supplies.

It's also got a nasty design fault. If the fuse comes out of the plug
when it's removed from the socket, you've got a live metal pin
sticking out.

Yes - I've seen that happen. They also had dreadful cord grips. Just a
rubber grommet.

--
*I started out with nothing... and I still have most of it.

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

On 02/07/17 12:58, Brian Reay wrote:


I'm pretty sure a relative who had a house built to his specification
has some sockets which are like that. The lighting (and other
'electrics' are computer controlled. There are several small switch pads
in each room and you can control most, if not all, the light etc in the
room from them. Some have remote control. All a bit complicated if you
are a visitor ;-)

It all works very well and is quite impressive but he did comment that
the system was already obsolete (it was installed 15+ years ago) and,
if anything failed, he may have issues replacing modules. I was curious
how it was configured but didn't get the opportunity to discuss it in
detail.

A bit like this then ... just skip to the last couple of minutes.

Some Mothers Do 'Ave 'Em
https://www.youtube.com/watch?v=qCxv64kqg4k

--
Adrian C

On 02/07/2017 11:42, Dave Plowman (News) wrote:
In article ,
Phil L wrote:
To switch a portable light, from a normal light switch, it is usual to
use an uncommon plug and socket, to avoid someone plugging the likes
of a vacuum cleaner into it - a 5amp socket fits the bill.

It's far more likely in order to deter guests from taking the bedside
lamps home with them.

You need to be a lot more careful of your guests.

:-)

--
Adam