Re: Fuse for coffee maker

Thanks. This was my line of thinking too but, to answer the question, I did wonder if a 5 amp fuse running so close to its rating could start getting hot. I suppose for an appliance only running for a few minutes at a time, this should not be a concern. 5A it is with a screwdriver on stand-by.

The logic of 13A is that it only needs to provide "fault protection" for the flex of the appliance, and that will have likely been designed assuming that it would be running on a circuit protected by a 16A MCB. So a 13A fuse would do that just fine. (it would also mean that you can plug other devices into the socket without needing to check the potential load of them)

(or you could also just cut off the pre-fitted plug and put a normal BS1363 "type G" on instead)

A 5A would probably work ok - it is only a short term load anyway, and a

Probably depends on the retailer, and the laws that apply in their host country.

The warranty is presumably with the manufacturer, and they might require the item to be returned to the country it was originally sold. I don't think this is anything to do with Brexit, as some companies provide worldwide warranties, but most don't.

I have always been puzzled by this. When I was I boy, I was taught that the size of the fuse related to the appliance and was designed to protect the appliance from a fault causing excess current. I have seen many times the explanation that it is the flex not the appliance that is being protected. Does this mean that all the appliances in most of the world have to be fitted with a 16 amp flex even though the load is nowhere near that figure? This must be highly wasteful. I have seen lamps on sale in Denmark with a flex I very much doubt could carry 16 amps (more than a three kW electric fire). Am I missing something?

No need when fortuitously I have a Schuko socket in the kitchen.

This was Mark's advice too. Short term load as I am trying to cut back on coffee consumption.

They have allowed me to register it, so I think they are stuck with it :-) Interestingly, I see the manufacturer is now Versuni, using the Philips name under licence.

On Mon, 2 Feb 2026 10:34:26 -0000 (UTC), Tricky Dicky snipped-for-privacy@sky.com wrote: [snip]

By that logic, why are we always told that the purpose of the fuse is to protect the cable not the appliance, when the reality appears to be that it is designed to protect the cable and the appliance?

1. The fuse size should indeed be related to the appliance.
2. The cable used on the appliance _also_ will be selected to suit the appliance - a small tablelamp will have a thin cable, whilst a 3kW electric fire will have a heavy duty cable (probably 2.5mm2).

Hence, in selecting a fuse to protect the cable, you are also selecting a fuse which is proportionate to the appliance at t'other end of that cable.

Thanks. That's what I thought. I don't know why this myth circulates that the fuse *only* protects the cable. I'll go with a 5A fuse for the coffee maker and if this fails I'll substitute a 7A fuse.

I think you are missing the point. The size of the fuse and supply cord are related to the wattage of the appliance an over current fault in the circuit would only occur if the appliance itself was faulty such as a short circuit in this circumstance the supply cord could end up carrying a current it was not rated for so the purpose of the fuse is to protect the cable from that current surge which could result in melting cables and/or a fire.

Does the same principle not apply to the internal wiring of the appliance?

You are protecting the cable from the device going faulty as it could cause an over current situation.

Because any reputable appliance will have a fuse or other protection inside, suitably matched to the possible failure modes. It's inside so an incorrect replacement is unlikely to be fitted if it blows. 'No user serviceable parts inside'. The plug fuse is there to deal with cable faults.

Leaving aside the philosophical distinction between intended and unintended consequences, can we agree that in general terms a lower-rated fuse is safer than a higher-rated fuse?

In general, yes, but it won't help if the lower-rated one cannot handle the start-up current and frequently blows. It may need to be changed to a slower-blowing type, which of course is impossible with BS1362 fuses.

Be wary of measuring the steady current. I once saw a situation where a higher-current PCB was fitted to an existing product, and after a few hours, the 5V fuse blew. I put two AVOs in parallel to measure the current, as few meters could read more than 10A at that time. I got a steady 18A reading, but I could see the fuse element sag, and eventually break. The fuse was a 25A one, which should absolutely never blow at less than 25A.

After a while, it occurred to me to stick an oscilloscope on the 5V supply, which turned out to be a poorly smoothed switching regulator input, with a low mark to space ratio. RMS current was calculated at about 35A, average about 18A.

I fit the lowest value I know will satisfy the load, without blowing, consistent with it also protecting the cable/flex, from overload too.

Exactly, this was my contention also. I agree that blowing the fuse on a coffee maker could be a serious matter.