On 20/11/2016 02:28, wrote:
On Sunday, 20 November 2016 00:11:32 UTC, John Rumm wrote:
On 19/11/2016 20:13, tabbypurr wrote:
On Saturday, 19 November 2016 18:56:25 UTC, John Rumm wrote:
On 19/11/2016 15:34, DerbyBorn wrote:



I will stick to fusing with the lowest capacity fuse to suit the current of
the appliance. I want the fuse to blow as soon as possible if there is a
fault.

Nothing wrong with fusing appropriately, but when dealing with fault
currents (in the technical sense), it makes little difference if its a
3A or 13A fuse when you try drawing 300A through it.

When you have an extension lead plugged into another, or an old appliance, or something bought from China, it certainly does.

You won't get a adequate fault current through too many cascaded leads,
but fitting all extension leads with 3A fuses in case someone may
cascade them seems a bit self defeating.

Plug fuses are available in 2A 3A 5A 7A 10A & 13A rating. Fitting the correct one to leads is hardly self defeating, it prevents fires.

How do you chose the "correct" fuse for an extension lead (assuming the
lead is designed for a 13A load)?

Are you proposing changing the fuse in the plug depending on what you
have plugged into the far end?

(and for most people the choice of fuse is 3, 5 and 13A - while non
standard options are available from more specialist places, they are not
commonly found in most shops)

Fault protection is what prevents fires. Modern kit built to recognised
standards will be adequately protected by a 13A fuse in the vast
majority of cases.

Ancient kit may require lower fusing, however I would not expect most
modern users to to be able to identify it.

Substandard imported tat is another matter - plenty of it does not even
have provision for fusing!


--
Cheers,

John.

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