Re: Why does laptop PSU have an earth wire?

Spiny Norman wrote:
On Tue, 21 Mar 2006 10:16:19 +0100, "John of Aix"
<j.murphy@xxxxxxxxxxxxxx> wrote:

Chris Whelan wrote:
John of Aix wrote:

So how come the rest of the world that uses two pins doesn't end up
electrocuting itself?

Sorry if this is patronising, but you did ask!

There are two methods of providing protection from accidental
contact. The first is surrounding in earthed metalwork. This is
Class
1. The second method is providing insulation that is additional to
the functional insulation. Guess what? This is Class 2!

Possibly for traditional reasons, but also because supply voltages
were often lower, countries other than the UK have tended to prefer
Class 2. The variation is also related to differences is the
distribution system.

The rest of the *civilised* world doesn't use two pin plugs and
sockets, but they often use just a scraping earth type of connector
where the earth connection may not be readily seen.

My sister and a few friends have laptops from the US, two friends
have laptops from Germany, many here (obviously) have laptops from
France and not one single one of them has a three pin plug therefore
no earth to..erm..ground. Are none of them in the civilised world
then (OK? I'll perhaps give it to you for the USA ;-) )


All the french plugs I've ever had were 2 pin with an earth strip on
the edge of the plug to connect to the earth on the socket. The two
I've had for laptops were the same with a three hole connector to the
PSU. I'd assumed the earth was connected to a screen in the psu but
I've not had reason to have one stripped to find out.

There are two (or in fact three, but the third is for high amperage
things like cookers and ovens) and one has an earth connector, but all
the portables and almost every other low powered equipmenet has two and
there are no more electrocutions in France than anywhere else. This
three pin (fused) giant plugs for equipment that is usually smaller than
the plug itself is absolutely needless. Anything that goes through a
transformer is not earthed as the transformation is done by induction.
The convertor may be earthed but the equipement isn't, it usually runs
at 9-20 volts and a few milliamps, the danger is zilch.



.

Relevant Pages

  • Re: Why does laptop PSU have an earth wire?
    ... where the earth connection may not be readily seen. ... France and not one single one of them has a three pin plug therefore ... All the french plugs I've ever had were 2 pin with an earth strip on ... I've had for laptops were the same with a three hole connector to the ...
    (uk.comp.misc)
  • Re: American and British (English)
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  • Re: American and British (English)
    ... laptops, everything changes, in the UK anyway. ... get a three-core 5 amp flex, ... and therefore needs an earth and a more robust ... So the heavier three-wire connector and cable isn't confined to UK ...
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  • Re: Why does laptop PSU have an earth wire?
    ... The rest of the *civilised* world doesn't use two pin plugs and ... where the earth connection may not be readily seen. ... My sister and a few friends have laptops from the US, ... I've had for laptops were the same with a three hole connector to the ...
    (uk.comp.misc)
  • Re: Non-magnetic screwdrivers
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