On 07/11/2012 21:40, Dave Liquorice wrote:
On Wed, 07 Nov 2012 20:47:53 +0000, polygonum wrote:

All modern appliances and leads are required to be safe with a 13A
fuse. However the reality is that fires do happen, and there are at
least some faults where a 3A would blow before a 13A, so maybe
preventing a small percentage of fires.

Please can you provide a reference to when that changed? And, ideally,
what the requirements actually are - in an accessible form.

That would be interesting.

The big bad assumption made in the digital spy thread was to assume only
short circuit faults and that massive currents will flow. In that
particular case there is little difference between a 3A or 13A fuse.

However if the short circuit current is only high, maybe limited by weak
spring tension in the fuse holder, corosion of the holdler/fuse cap,
dodgy wire termination some where, and say only 20A is flowing. Thene
there is a significant difference between a 3A and 13A fuse.

If there is only 20A of fault current, then there is 11.5 ohms of
resistance somewhere! The 4kW you are dissipating in the fuse holder
might be more of a worry than whatever is going on with the flex ;-)

--
Cheers,

John.

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