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Authored by: Wol on Monday, June 03 2013 @ 07:06 PM EDT |
Simple.
Everybody thinks that the neutral wire has no potential. But if you've got a
working appliance, then the live and neutral are connected and there IS a pd
across the neutral. It's only the earth that is - supposedly - at 0V.
Now, have you heard of single and double pole sockets? A single pole socket only
has the switch in the live wire, the neutral is still connected. Stick your
finger in the neutral hole, and if there's something switched on elsewhere on
the main then there's a pd on neutral and you'll get a shock.
A double pole socket disconnects both live and neutral so you won't get a shock,
but not surprisingly they are less common because they are more expensive.
That's why the earth pin on UK plugs is longer than the other two ... there is a
shutter inside a UK socket that blocks any attempt to push anything into the
live or neutral holes. Only after the earth pin has gone in and pushed the
shutter out of the way are the holes clear for the live and neutral pins. I've
had an extension lead ruined because the earth bit of the shutter broke so you
could no longer put a plug in.
Cheers,
Wol[ Reply to This | Parent | # ]
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