On Wed, 04 Jan 2012 17:50:18 -0000, Ian wrote:


"Tim Streater" wrote in message
...
In article ,
John Rumm wrote:

On 04/01/2012 15:20, Lieutenant Scott wrote:
On Wed, 04 Jan 2012 13:29:16 -0000, John Williamson
wrote:

Lieutenant Scott wrote:

Not a lot to do with the thickness of the prongs - they are capable
of
carrying WELL over 30A in all probability.

Just how thick is the actual conductor inside the sleeved bit?

It has a greater area than the wires connecting to the plug, and with
a
*much* lower resistance than the connection from the wire to the pin,
or
the wire in the fuse.

As has already been said here, the weak points of *any* temporary
mains
connection are the fuse, the connections to the fuse, the connections
to
the wires, and the sprung contacts in the socket.

Recent (within the last fifteen years or so) improvements include
welding the wire to the pins inside the plug, which was introduced to
improve the reliability of pre-wired plugs, and improving the design
of
the fuseholder from the old style with two narrow prongs contacting
the
fuse to the current standard of two wider, shaped holders, and a
holder
for the fuse which means that it can be changed without tools.

Honestly, this just happened by chance, and has nothing to do with me
already being in this thread!

I plugged this into the mains and wondered why the laptop wasn't
charging properly, it kept going off. I removed the plug, intending to
try another lead, and left the neutral prong in the socket!

http://petersphotos.com/temp/plug.jpg

Bring back the big old British ones with hefty round pins! Any reason
we
changed from those?

They were unfused and hence could not be used on a high power circuits,
and they were unshuttered with all the risks that that entails. As the
modern home is stuffed with ever more low power devices, the need for
sockets with ever greater current capacity would seem to be waning.

And there were several physical sizes. So we had two sizes of socket at
the wall. I remember these clearly from 1951 or so. See BS 546.

2pin 3A
3pin 3A
3pin 5A
3pin 15A
3pin (round pin, fused pin) 13A
Clock outlet.

I may have left one or two out.

I only remember the 5A and 15A round pins, but then I was born in 75 - maybe the others went away earlier than that?

I remember a woman telling me that she had to get her house rewired to change to 13A sockets. She was convinced that you could not possibly draw 13 amps from a 15 amp outlet, as it was a different kind of electricity. And those little adaptors she had were converting it.

Today, we have 3 pin "13"A.
(which sometimes can be seen in two vertical current-carrying, with
horizontal earth pin, configuration. Often used where there is a need for a
socket outlet, where you don't want any unauthorised items being pugged in).

You mean someone stealing electricity for clay-making? http://youtu.be/1Bi63Hi51sQ

--
http://petersparrots.com
http://petersphotos.com

Why is the front of an aeroplane called a cockpit?
If you have female pilots do you call it a pussypit?