I've been cogitating on the fusing factor of 1362 fuses (specifically 13A fuses) and how this correlates with the protection of a 1.5mm2 flexible cable. As ever I am hoping you can shine a light!

It is a setting where a circuit experiences a current that is higher than the normal operating current. The operating characteristics of a device protecting a conductor against overload shall satisfy the Reference 4F3A a 1.5mm2 single phase AC flexible cable has a tabulated current carrying capacity of 16amps. 16x0.763 = 12.208 amps which is obviously less than the 13 amp rating of the fuse. Leading on to… 433.20/202 where an allowance is made for the fusing factor of a 3036 fuse. If the fusing factor of a 1362 is at 1.9 it is fairly comparable so surely we must apply a comparable derating factor? This is where the wheels come off my bus if the answer is more than just… It doesnt protect against overload. Where I'm getting turned around. The current (I2) causing effective operation of the protective device does not exceed 1.45 times the lowest of the current carrying capacities (Iz) of the conductors of the circuit.The length of the fuse is too short. A plug top fuse should have a length of between 25.0 - 26.2 mm. The diameter of the of the end cap measures 6.05mm and does not meet BS 1362 either. It should be 6.25 - 6.5 mm

Breaking capacity is the level of current that the fuse can safely handle without exploding or breaking. The breaking capacity of your fuse should be greater than the fault current of your electronic circuit. The dimensions meet the BS1362 requirements and it also contains a sand filling. If it were not for the incorrect licence numbers being printed on the fuse, there would be no reason to suspect that these were counterfeit. The length of the fuse measures 24.91mm. A BS1362 fuse should have a length of 25.4mm with a tolerance of +0.8/-0.4mm.

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The non-fusing current, the current that the fuse is capable of carrying, is specified as 1.6 times the rated current (I nf = 1.6 I n). The fuse must be capable of carrying the non-fusing current for at least 30 minutes. So a 13A fuse must be capable of maintaining a current of 20.8A for at least 30 minutes without blowing. Fusing Current Look at these curves and look at the ‘all blow’ right hand curve, vs the left hand ‘never blow’ limit for 13 and 3A fuses. The combined weight of the 9 fuses is 18g. The weight of 9 genuine fuses on the same scales is 23g. This indicates that they probably do not contain the required sand filling. The fuses have the ASTA approval symbol and appear to be branded 'CF' and marked AF63. (A BS1362 fuse must have the manufacturer's name or identifying mark.) They also have a number printed on them: SS157.