On Wed, 23 Nov 2016 00:01:53 -0000, John Rumm wrote:

On 22/11/2016 22:47, wrote:
On Tuesday, 22 November 2016 20:23:21 UTC, John Rumm wrote:
On 22/11/2016 12:06, Roger Hayter wrote:

Realistically the fuse is not going to provide overload protection, just
fault protection for the flex for modern small electronic appliances. I
thought that was what you said earlier in the thread?

Indeed it is. I was just trying to get the bottom of what Nige was
actually attempting to achieve with his lowest possible fuse that's
adequate scenario - I understand the adequate bit - it must offer fault
protection, but assuming we have got past the "it gives adequate fault
protection" stage, there seem to be diminishing returns.

Depending on the appliance, it could end up being an exercise in blowing
lots of small fuses working your way up to the optimal one.

Most appliances are not going to need specific overload protection and
many that do may include a 750mA (or whatever) 20mm glass cartridge
fuse for the purpose. Those alone though won't provide fault protection
(inadequate breaking capacity usually), so sny BS1362 fuse in the plug
will do in many of those cases.

But a small significant percentage of appliances have neither short nor overload protection on a 13A fuse. Why you don't get that I really don't get.

I "get" that crusty old crap, and 5A extension leads need specific fusing.

I also get that if one understands these things there is no harm in
selecting a lower rated fuse.

However we live in a world where appliance designers accept that many
users won't be able to make a judgement call on this, and hence
designing them to remain safe on a 13A fuse is the only prudent option.

So you want every appliance to have a 13A cable? That's a bit daft.

--
Why was the "pap smear" called that?
If it'd been called the "**** Scrape," no one would ever have it done.