<story><title>Brilliant design: RCA student radically improves the UK plug</title><url>http://www.iconeye.com/index.php?view=article&amp;catid=1:latest-news&amp;layout=news&amp;id=3864:rca-student-radically-improves-the-uk-plug&amp;option=com_content&amp;Itemid=18&amp;ref=nf</url></story><parent_chain><item><author>cstross</author><text>There&apos;s also a second reason British plugs are robust and fused: they&apos;re built to carry up to 3 kilowatts at 230 volts. (None of your wimpish American 110 volt mains juice here! Nothing quite makes your hair stand on end like accidentally touching a live pin carrying 230 volts and 13 amps ...)&lt;p&gt;To that end, the live and neutral contacts in a British socket are shuttered. The long earth pin on the plug makes contact before the live or neutral pins are in the socket, and once in contact, raises a shutter to permit live and neutral to make contact. And the nether regions of those pins are insulated so that if a plug is halfway into a socket and something bridges the pins, it can&apos;t make contact.&lt;p&gt;This is a great design -- for space heaters and ovens and server racks. It&apos;s a bit less useful for the low power consumption devices that have come to dominate the market (where maximum draw is well under 1Kw -- often under 0.1Kw).</text></item><item><author>ars</author><text>Tiny bit of history:&lt;p&gt;The reason plugs in the UK are so big is that each one must be individually fused. And the reason for that is something called a &quot;ring circuit&quot;.&lt;p&gt;In a ring circuit you have, say, a 40 amp fuse at the mains/box. From this you send out two wires, each rated only for 20 amps, going in a circle around the house. You can now supply 40 amps worth of power using only cheaper 20 amp wires. (Since the current can flow over both wires at once.)&lt;p&gt;But this means that the wires going to an individual appliance are far too small for the main breaker, so each appliance gets a fuse in the plug.&lt;p&gt;Ring circuits have serious drawbacks, but they helped during a time when there was a copper shortage.&lt;p&gt;And ever since then the UK has been stuck with huge plugs.</text></item></parent_chain><comment><author>masklinn</author><text>&amp;#62; There&apos;s also a second reason British plugs are robust and fused: they&apos;re built to carry up to 3 kilowatts at 230 volts. (None of your wimpish American 110 volt mains juice here! Nothing quite makes your hair stand on end like accidentally touching a live pin carrying 230 volts and 13 amps ...)&lt;p&gt;Mainland european grounded plugs pretty much all handle 15A/230V, and none looks like a battlecruiser (see the well-known and widely used &quot;CEE 7/7&quot; aka &quot;Type E/F hybrid&quot;: &lt;a href=&quot;http://en.wikipedia.org/wiki/File:CEE_7-7.jpg&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/File:CEE_7-7.jpg&lt;/a&gt;)</text></comment>
<story><title>Brilliant design: RCA student radically improves the UK plug</title><url>http://www.iconeye.com/index.php?view=article&amp;catid=1:latest-news&amp;layout=news&amp;id=3864:rca-student-radically-improves-the-uk-plug&amp;option=com_content&amp;Itemid=18&amp;ref=nf</url></story><parent_chain><item><author>cstross</author><text>There&apos;s also a second reason British plugs are robust and fused: they&apos;re built to carry up to 3 kilowatts at 230 volts. (None of your wimpish American 110 volt mains juice here! Nothing quite makes your hair stand on end like accidentally touching a live pin carrying 230 volts and 13 amps ...)&lt;p&gt;To that end, the live and neutral contacts in a British socket are shuttered. The long earth pin on the plug makes contact before the live or neutral pins are in the socket, and once in contact, raises a shutter to permit live and neutral to make contact. And the nether regions of those pins are insulated so that if a plug is halfway into a socket and something bridges the pins, it can&apos;t make contact.&lt;p&gt;This is a great design -- for space heaters and ovens and server racks. It&apos;s a bit less useful for the low power consumption devices that have come to dominate the market (where maximum draw is well under 1Kw -- often under 0.1Kw).</text></item><item><author>ars</author><text>Tiny bit of history:&lt;p&gt;The reason plugs in the UK are so big is that each one must be individually fused. And the reason for that is something called a &quot;ring circuit&quot;.&lt;p&gt;In a ring circuit you have, say, a 40 amp fuse at the mains/box. From this you send out two wires, each rated only for 20 amps, going in a circle around the house. You can now supply 40 amps worth of power using only cheaper 20 amp wires. (Since the current can flow over both wires at once.)&lt;p&gt;But this means that the wires going to an individual appliance are far too small for the main breaker, so each appliance gets a fuse in the plug.&lt;p&gt;Ring circuits have serious drawbacks, but they helped during a time when there was a copper shortage.&lt;p&gt;And ever since then the UK has been stuck with huge plugs.</text></item></parent_chain><comment><author>jergosh</author><text>&lt;i&gt;And the nether regions of those pins are insulated so that if a plug is halfway into a socket and something bridges the pins, it can&apos;t make contact.&lt;/i&gt;&lt;p&gt;That&apos;s not really true, you can still get electrocuted if you put you finger on both bolts.&lt;p&gt;And that plug is &lt;i&gt;massive&lt;/i&gt;. Luckily you can use any sticklike thing to allow continental plugs to be inserted (which incidentally I&apos;m doing right now -- hello from Edinburgh)</text></comment>