On Tue, 22 Nov 2016 20:23:19 -0000, John Rumm wrote:

On 22/11/2016 12:06, Roger Hayter wrote:
John Rumm wrote:

On 21/11/2016 21:19, wrote:


And for the sake of clarity, I shall now state what I thought was
obvious, but perhaps isn't to some. A 5A extension lead is usable for
loads up to 5A continuous, and is thus best protected by a 5A fuse.

Obvious enough - you need the fuse for fault and overload protection in
that case. One of the reasons why 5A leads are far less freely available
than in the past.

The fact the fuse can't provide overload protection in the common
circumstance of the lead being used without being unreeled is probably
why they often have heat operated overload cutouts in the reel.

For extension leads on a reel, yes.

There is a second class of lead which are the multiway sockets on a
(typically shorter) lead. There the 13A fuse also has to provide
overload protection since its possible for the user to abuse them. (and
this is also a cases where I would have some sympathy with fittings say
a 10A fuse to some of the cheaper examples of those since tests have
shown a number to not really be capable of sustained 13A load).

Dunno if it was the fuse allowing 13 amps through, or the extension not allowing 13A continuous, but I've seen someone melt 4 way strips by plugging in two tumble driers and two washing machines. They really should make a 13A fuse melt if it gets 14A for more than a minute.

--
Drive defensively. Buy a tank.