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Lucien Nunes · 7th Jul 2019, 10:14 pm

The time/current characteristics of 3A and 13A plug fuses are given in the link in GrimJosef's post above. A 13A fuse is not expected to operate below 21.6A (1.66xIn), above that, how long it takes depends on the current as shown by the curves.

I think you are overlooking the important point that cable ratings are calculated with reference to the fusing characteristics of normal fuses and circuit breakers. Cable rated at 13A will tolerate 50A for the few seconds it would take a 13A fuse to blow. The rule as I mentioned above is that the cable rating (once corrected for ambient temperature and any other derating factors if applicable) must be no less than the fuse rating, and the fuse rating must be no less than the continuous load of the appliance. If those conditions are satisfied, it is safe, because the behaviour of the fuse has already been taken into consideration when publishing the ratings.

7th Jul 2019, 10:14 pm	#94
Lucien Nunes Rest in Peace Join Date: Apr 2008 Location: London, UK. Posts: 2,508	Re: 13 amp fuse for 1.5mm mains flex? The time/current characteristics of 3A and 13A plug fuses are given in the link in GrimJosef's post above. A 13A fuse is not expected to operate below 21.6A (1.66xIn), above that, how long it takes depends on the current as shown by the curves. I think you are overlooking the important point that cable ratings are calculated with reference to the fusing characteristics of normal fuses and circuit breakers. Cable rated at 13A will tolerate 50A for the few seconds it would take a 13A fuse to blow. The rule as I mentioned above is that the cable rating (once corrected for ambient temperature and any other derating factors if applicable) must be no less than the fuse rating, and the fuse rating must be no less than the continuous load of the appliance. If those conditions are satisfied, it is safe, because the behaviour of the fuse has already been taken into consideration when publishing the ratings.