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Graham.[_11_]

On 13/05/2018 19:59, wrote:
On Sunday, 13 May 2018 14:07:39 UTC+1, Steve Walker wrote:
On 13/05/2018 13:24, Harry Bloomfield wrote:
It happens that Robin formulated :
Yes, but the context of the text I quoted was a *different* point -
viz "I have never understood why *wholly* [emphasis added] plastic
earth pins are not allowed."

I would imagine that is because if a brass pin is actually needed, the
partially sleeved ones have more of a tendency to break. On something
which requires an earth, the last thing you want is an internally broken
earth pin, which might still allow you to plug the plug into a socket.

Plastic earth pins are allowed on the likes of phone chargers, even
folding ones. There, just to push the shields out of the way.

You haven't read the webpage linked to have you? It clearly says "To
ensure that the earth connection is made as soon as the plug touches the
socket many sockets place the contact right at the faceplate, this means
that continuity is lost as soon as a plug with a sleeved earth is fully
inserted!" Hence why earth pins are only allowed to be all brass (or all
plastic if an earth is not required for the device).

SteveW

that explanation does not make sense.

Of course it does.

To ensure that the earth pin makes contact well before the live and
neutral (and breaks contact last on unplugging), the earth contact
within the socket is as far forward as possible, while the live and
neutral are a little further back. For the same reasons, the earth pin
is longer than the live and neutral pins. If an earth pin is partly
sleeved, the metal part can have slid right through the contact and the
contacts be only resting on the plastic sleeve - hence no earth
connection. To prevent this, sleeved earth pins are specifically banned.

Non-earthed appliances don't need the earth pin at all, so it is
acceptable for them to have a fully plastic earth pin, purely to open
the shutters on the socket.

SteveW

It dosn't explain why a s
--

Graham.
%Profound_observation%