On 20/08/2018 14:10, Terry Casey wrote:
In article ,
says...


Aren't all flexes fitted to a 13 amp plug meant to be able to blow even a
13 amp fuse in event of a short? But not necessarily handle the full 13
amps long term?

No, no, no, no ,no!

Actually, these days yes...

But note we are talking about the specific case of a short circuit, not
a continuous overload.

(refer to the adiabatic calculation I did a couple of posts back - the
minimum fault withstand cable CSA was less than 0.5mm which is typically
the smallest flex size in common use these days. However all best are
off if the flex is on the end of a long extension lead)


The sole purpose of the fuse in the plug is to protect the
flexible cable connected to it and should, therefore, be rated
accordingly.

If you fit a 13A fuse to a plug fitted with flex rated at 3A
and another idiot connects the other end to a 3kW load, what
do you think might happen?

It would get very hot... the insulation may fail to the point where it
then shorts and the fuse blows.



--
Cheers,

John.

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