Nartel® BS1362 Fuse Cartridge 13 amp for UK plugs (Pack of 10)

Product Information

Breaking the fuse open confirms that these fuses are counterfeit. There is no sand filling. The quartz sand inside a genuine BS1362 is designed to control the rupture of the fuse wire within the ceramic body. Is there another factor at play here which I am missing? Or do I just have the wrong fusing factor! I appreciate that there will be manufacturers tolerances both for the device and the cable (which could go both ways) and that there is undoubtedly going to be some headroom in the cable. I've seen a plumber leave a 9.0kW electric boiler on a bit of 1.5 flex before and yeah (prior to me fixing it) it was pretty hot after a few hours but it hadn't melted! Is the answer just that we're only talking about an extra amp in the example and whilst it may get a bit hotter than would be ideal this isn't the end of the world or are we into the realms of trying to work out how much heat is being dissipated during the fault by the flex as it is going to be happening over quite a prolonged timeframe?

At the beginning, 100% of the heat generated in the live conductors is available to heat the cable. At 21 deg C, only 98% of the heat is available because the loss is 1/50 of the amount at the steady state. At 22 deg C, only 96% is available and so on. So looking at 1 deg C increments, it takes in fact 45 min to get to 69 deg C and you never quite get to 70 deg C. Please forgive me for having forgotten the calculus which I learned 45 years ago.

The shiny metal end caps are also a good indicator that the fuse is not genuine. The end cap on the genuine Cooper Bussmann fuse is not as shiny. This fake fuse also has a larger than normal dimple in the end of the cap. Surprisingly the fuse does contain the sand filling required, most counterfeit fuses do not have any filling. The sand is required to control the breaking operation of the fuse. Without this filling material, the air within the fuse expands as the fuse wire melts and arcs, causing the fuse to explode, as demonstrated in our previous article on fake fuses. In the spirit of learning from my betters I will lay myself open to ridicule! I'm faintly terrified at having my life changed though! ? These domestic plug fuses are ideal for protecting the flexible lead between theplugand appliances to prevent fires due to large currents. This range of fuses from Eaton Bussmann are fast-acting with high rupture capacity. They are suitable for various different uses, providing reliable performance and cost-effective circuit protection. They are ideal for use in plugs to protect cables from melting or catching fire if they are overloaded.

The manufacturing standard of these fuses is particularly poor. The fuse wire is simply trapped between the end cap and body. A genuine BS1362 fuse has the internal wire connected to an eyelet inside the centre of the cap. 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. Part 2: Overcurrent: A current exceeding the rated value. For conductors the rated value is the current carrying capacity.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 operating characteristics of a device protecting a conductor against overload shall satisfy the The outcome of all this is to not worry about these minor domestic overload problems, as one can see from the normal use one sees, they rarely cause any trouble at all. Loose connections are the cause of problems, not overload of cables. The rated current or current setting of the protective device (In) does not exceed the lowest of the current carrying (Iz) of any of the conductors of the circuit, and

The fusein a plugis a deliberate weak link in a circuit which will 'blow' if an electrical appliance or extension lead draws too much current due to either an overload or a fault. The operating characteristics of a device protecting a conductor against overload shall satisfy the following conditions:

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! Then I agree with the several mins figure for a 40 degree rise. The conductor only version is the basis of our old friend the adiabatic calculation, where it is so fast that the heat does not have time to stabilise to a uniform temp throughout the PVC, so we pretend that no heat is lost to the insulation at all, as the temperature rise calculated that way is always a safe over estimate, so we safely under estimate the let-through energy the cable can stand.

HBC stands for high breaking current and refers to the maximum current that the fuse can handle without breaking. It is also known as HRC (High Rupturing Capacity). 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. Now I did not quite use Chris's figure of 3 mins at 20 A, but if I had it would have scaled to 3mins/100 at 200A, or about 2 seconds for a 40 degree rise. I had a more optimistic figure, allowing a bit for the PVC, and as I did not have the regs with me, so used a pidooma figure from memory.This confusion (at least, in my mind!) seems to arise at least partially because 433.1.202 has been included completely unnecessarily, tempting one to think that BS3036 fuses are the only devices that require 'special attention/thought'. In reality, it is but just one example of a device with a 'fusing factor' which is not 1.45 (hence I 2 is not 1.45I n) , such that they could also have included (as another 'special case'), say, your BS1362 with a fusing factor of 1.9 (or whatever) ... or, better, not have this reg at all, and just let people work out I 2 for themselves.. 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 measures 24.91mm. A BS1362 fuse should have a length of 25.4mm with a tolerance of +0.8/-0.4mm. So there we are, a 2.5 sqmm cable loaded at 20 A will take over 45 minutes to get up to 70 deg C from 20 deg C enclosed in conduit in an insulated wall. Any smaller loading or less lagging and it will never get there because the heat generated in the conductors will always be less than the available heat loss.