| | Re: Mains / USB
"Whiskers" <email@example.com> wrote in message
> On 2012-03-01, Woody <firstname.lastname@example.org> wrote:
>> "Whiskers" <email@example.com> wrote in message
>>> On 2012-02-29, Andrew Benham <firstname.lastname@example.org> wrote:
>>>> On Tue, 28 Feb 2012 20:52:14 +0000, Andy Burns wrote:
>>>>> It will only take what it wants, it won't get more "pushed"
>>>>> at it by the
>>>>> power supply, e.g. when you plug a 40W bedside lamp into a
>>>>> 13A socket it
>>>>> doesn't run at 3kW!
>>>> This reminds me of the time when our house still had 15A
>>>> sockets, and I was making an adaptor lead to a flying 13A
>>>> socket. I
>>>> asked my physics master where I could get a suitable resistor
>>>> to carry
>>>> the extra 2 amps (120 ohm, 480 watts...).
>>>> [ This was a very long time ago. ]
>>> Ah, the good old days when school-kids played with handfuls of
>>> mercury and
>>> glass jars of nitric acid and 240 Volt mains, drinking water
>>> came through
>>> lead pipes, and 'safety precautions' meant 'roll your sleeves
>>> up and tuck
>>> your tie in' and 'use the asbestos blanket to smother the
>>> Our house had 15 Amp round-pin sockets and tiny 5 Amp sockets
>>> too, some
>>> with only two pins. Thank goodness it wasn't necessary to
>>> include a
>>> resistor (or diode or whatever) to soak up the surplus 10 amps
>>> on all the
>>> adaptors we had!
>> For the record, 5A plugs were not actually that much smaller than
>> 15A. If you mean the very small three-pin round then you are
>> likely talking about 2A plugs often used for table/bedside
>> lights. The two-pin sockets were the same size as a shaver plug,
>> very slightly narrower pin width and lightly thicker pins than a
>> Schuko. Rated 2A also but no earth.
> I think the Wikipedia article has it about right. The 'live' and
> pins on the 15A plugs are 1" from centre to centre, the 5A plugs 3/4";
> that doesn't sound like a big difference, but the 5A plugs actually look
> and feel a lot smaller than the 15A.
> As well as the assorted 2A sockets, we also had a few special electric
> clock sockets - very small 2-pin with a screw to prevent the plug from
> being pulled out.
> Our 5A sockets were wired in sets of 3 (not necessarily in the same room)
> to a single fuse on the fuse-board, instead of having just one 15A on that
> circuit. The 2A sockets were on the lighting circuits. The fuse-boards
> (I think there were at least four) were a nightmare, even with each fuse
> labled and a plan of the house matching fuse to socket.
When I was a kid, there was a two way bayonet adapter plugged into the
electric light pendant. One side of it took the light bulb and the other
was where you plugged in the electric iron. It was a perfectly normal
setup back then. Many houses only had electric lighting and (if it was a
more modern property) one or two 5amp (2 pin) outlets. To heat a bedroom
if one of us was poorly, or in cold weather the bathroom - yes, the
bathroom - , my father had a thirty foot lead on the electric fire and the
lead would trail down to the cupboard under the stairs where it plugged into
one of the two pin 5amp sockets. No circuit had an earth of any sort and
the house was only built in 1937. How things have changed.