Curious round 3 pin sockets in modern flat
Midge
flat built around 5 years back and I suppose you'd say it was rather posh
and well spec'ed.
Lounge/dining area has no less than two types of round 3 pin socket in
addition to the normal 13A plugs and our friend was asking if I knew for
certain what they were. One type is close to the pin spacing of a 13A, and
has the same sort of shutter opener on the earth pin. I see from my Screwfix
manual that some manufacturers have 5A round plug/socket listed so I assume
its one of those and probably used for lighting - but what is the reasoning
for putting them in such a modern property? I thought round pin sockets were
old rather than new!
The other type of round pin socket is smaller. There is no shutter opener
and my friend was once told it might be for surround sound system. This
sorta ties in - there is one adjacent to the TV aerial socket, and sockets
dotted around that end of the room where you might put speakers - but not
knowing anything about such systems, I'd have assumed they would be
individually cabled back to the TV so you'd have a row of them. I'll take a
tool kit next time to have a proper look but any ideas on this one?
TIA, Midge
Java Jive
wrote:
>
> Lounge/dining area has no less than two types of round 3 pin socket in
> addition to the normal 13A plugs and our friend was asking if I knew for
> certain what they were. One type is close to the pin spacing of a 13A, and
> has the same sort of shutter opener on the earth pin. I see from my Screwfix
> manual that some manufacturers have 5A round plug/socket listed so I assume
> its one of those and probably used for lighting - but what is the reasoning
> for putting them in such a modern property? I thought round pin sockets were
> old rather than new!
One possible reason for putting 3A (or was it 2A?) round-pin sockets
in a room is so that peripheral lighting plugged into them can be
controlled by a light-switch at the door. My parent's house was
completely rewired with flat-pin 13A ring mains in the early 1960s,
but in the main rooms there were also 3A plugs at floor level so that
standard lamps and table lamps could be controlled by wall-switches.
We hardly ever used the central-ceiling light.
> The other type of round pin socket is smaller. There is no shutter opener
> and my friend was once told it might be for surround sound system. This
> sorta ties in - there is one adjacent to the TV aerial socket, and sockets
> dotted around that end of the room where you might put speakers - but not
> knowing anything about such systems, I'd have assumed they would be
> individually cabled back to the TV so you'd have a row of them. I'll take a
> tool kit next time to have a proper look but any ideas on this one?
Can't help with that except to suggest that the lack of shuttering
suggests that it's not mains, so some sort of data connection such as
you suggest is a possibility. Or are they composite video connections
- if so they will consist of sets of 3 seperate 3mm sockets, one
coloured yellow (video) and the other two red and white (stereo
audio)? If they are CV, your friends probably wouldn't want to use
them, as CV is an inferior quality video connection commonly
associated with high levels of 'dot-crawl'.
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Midge
The idea of tying these sockets together to a master light switch does make
perfect sense now you mention it. The lounge/dining room is pretty sizeable
(over 30ft long) and lit with downlights, so you'd tend to have
supplementary lighting (uplighters etc.) dotted around. Use of 3 pin round
plugs would stop anyone putting anything heftier in them.
The smaller version is literally just that. At first glance you'd assume it
was just a lower rated/smaller version of the same (I'll find out for
certain when I'm next over there).
Midge.
Andrew Gabriel
Round 3-pin come in 2A, 5A, 15A (and 30A, but not normally in a home).
They are still permitted for use. If used in the home, shuttered versions
are required. As stated, the 2A and 5A are commonly used for outlets
powered from lighting circuits. The plugs are normally unfused, although
fused versions have been produced (and I think still are by MK).
I have two 2A ones in my living room, used for a table lamp and display
lighting built into a shelving unit, which run from the lighting circuit.
(As with all my lighting, it's controlled by computer. It feels like the
door switch controls it, but actually it just signals the computer and
can be configured to anything I want.)
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Midge
couldn't work out why you would have a 13A + 5A round + 2A round all in a
line as there is on one wall. They are polished chrome finish too so don't
exactly blend into the surroundings either!
Anyway, hopefully the mystery will be solved when I'm over that way again on
Monday.
Midge.
Midge
friend had always wondered what it did!).
The smaller sockets are 2A. Blue/brown twin core mains cable but no earth
(unless its somehow bonded across from the adjacent sockets. I was pretty
sure I was going to find them wired up to the downlights, but nothing I
switched on in the room got any of these sockets live. Checked the consumer
unit and no breakers out. So they remain a mystery and we're putting a call
into the management company to see if they know.
Java Jive
wrote:
> Bit of progress. The 5A sockets are all wired back to a wall switch (my
> friend had always wondered what it did!).
Where on the wall is the switch? Is it one of the light switches next
to a door, or somewhere else? Are the sockets on their own circuit
back at the consumer unit, or are they on one of the lighting
circuits, probably the same circuit as the lights in the room?
I ask because IIRC lighting circuits are only rated at 5A, so a single
socket rated at and consuming 5A could consume a circuit's entire
rating without anything else being switched on. I would definitely
have expected the 2A sockets, with or without switches of their own,
to be the ones wired to a wall switch, probably next to a door, and
the 5A to have their own switches and to be on their own circuit with
higher rated cabling.
> The smaller sockets are 2A. Blue/brown twin core mains cable but no earth
> (unless its somehow bonded across from the adjacent sockets.
Are you saying that the sockets have earth sockets which are not
connected to earth???????????????????????
> I was pretty
> sure I was going to find them wired up to the downlights, but nothing I
> switched on in the room got any of these sockets live. Checked the consumer
> unit and no breakers out. So they remain a mystery and we're putting a call
> into the management company to see if they know.
I find this rather surprising! And, depending on the unknowns that
I've questioned, possibly dangerous? I wonder if some cowboy
electrician, young enough not to remember the round-pin 15A, 5A, and
2A circuits of yesteryear, miswired them?
js.b1
which makes me wonder what "2-core cable" has been used? You can use
flex, but the ends should be prepared accordingly to terminals not
suited to flex (ie, bootlace ferrules).
Could be someone planned on 12V with remote transformer, hence the
lack of an earth.
Either a bad requirements spec, or something trying to do "both" mains
& 12V and ending up with an abomination :-)
Lobster
I'll bite...
How does that lot work, then?
David
Midge
on what circuit on the consumer unit yet as I only had about 15 minutes to
dig about. I agree, this doesn't feel right in any event as there are half
a dozen of the 5A sockets around the room so the load could easily exceed
the switch - even if they turn out to be on their own cct breaker.
All I can think of on the 2A is whether they were intended for something
other than mains.
Hopefully I will get a bit more time to dig around next time I go.
"Java Jive" <ja...@evij.com.invalid> wrote in message
news:1thuc6tqlg6b4nkak...@4ax.com...
Midge
(no earth) that has been used on that. So all I can assume is it was
intended for some other (i.e. not mains) service. I've left this with my
friend to quiz the management company for the flats.
"js.b1" <js...@ntlworld.com> wrote in message
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