"David WE Roberts" wrote in message
...

"David Robinson" wrote in message
...
Not my question, or belief, but found here...

http://forums.digitalspy.co.uk/showthread.php?t=1755197


Is there a counter-argument?


Just to note that I've just replaced the 5A fuse in an extension lead for
the second time in a week.
Rated 4A coiled and 5A uncoiled.
We use it for lights but passing builders tend to plug anything into
anything.
So yes, the fuse does protect the cable :-)

You are correct, but a little slower - it may go to 4A before the fuse
breaks. If current is say 1A and the fuse 3A, then the current increases for
whatever to 4A the fuse may not break so quick, but will eventually, so
giving protection. The fuses are designed for fault current, which means, as
one poster in the link stated a 3A and 13A will break as quick as each
other - on a fault.

I only scanned the link, but one poster I think was saying have all fuses
13A. So if he had a lamp with 0.25mm flex and 13A fuses he thinks he is
safe. OK on a lamp it is difficult to see how the current would be great
enough to melt the cable as the bulb would blow way before any current is
dangerous enough. They only time the current would be high enough to melt
the flex would be if there is a fault, which would be momentarily and the
fuse would then snap. I "think" that is what is he on about. He says the
13A fuse will break faster on a fault than a 3A. BTW, I recall as a kid my
sister's cheap Italian (looked good though) table lamp switch melting. It
obviously had a "fault" and" a 13A fuse. A 3A fuse would have snapped
stopping the melting, which was a fire hazard. The switch could be classed
as a part of the cable and the appliance the light bulb.

The secret? As fuses have dropped into 3A and 13A in common use (Only
specialist outlets sell anything else these days) never install flex that is
rated less than 3A and fit correct sized fuse to protect the cable. The
cable should never be rated less than the fuse.

Some fit larger rated fuses because of surge. If there is surge then fit
anti-surge fuses, not a large rated fuse.