Slow blow BS1362 fuse?

Does it need to be specifically BS1362, or just fit that sort of fuseholder? There are 25mm x 6.3mm fuses of various kinds.

Those it seems like there are those marked BS1362:

snipped-for-privacy@aolbin.com wrote in news: snipped-for-privacy@mid.individual.net:

I haven't checked but my guess is that it is a specific requirement of BS1362 for the fuses to be fast blow hence why you will not find any sold as meeting that spec. Having looked at the Forest Master page however I wouldn't be concerned about using them. What was it about the description that made you wary?

I have a variant on this. I have now installed a Schuko socket in the kitchen. I know this cannot be connected direct to the 32 amp ring main, so the electrician included a fused spur and 13 amp fuse. I think 13 amps is too high. The main item is a coffee maker rated at

The question is really out of curiosity as I could fit any fuse and change it if required.

Wow! A 1.55MW coffee maker! I think you missed the point! :)

The last I heard, and it was some years ago, the type of fuse used for BS1362 (i.e. plugs and fused spurs) is filled with sand or similar and provides close overcurrent protection, meaning that it is guaranteed to fail within four hours at 1.5 times the rated current. Circuit breakers are also in this class. Coarse overcurrent protection will fail within four hours at twice its rated current, and includes ordinary glass fuses and rewireable fuses.

No, they're not exactly precision devices.

Re BS1362 spec: a good point.

It was this, slightly odd, text that put me off: "Here are a few scenarios in which a time-delay fuse would solve your issues: – Electric Log Splitter is producing a humming noise and is not operational. – Electric Wood Chipper is cutting out at startup. – Electric Wood Chipper is generating a humming noise while not being operational". It made me wonder whether it was a genuine seller - but it's academic because their website isn't working for Paypal sales.

I'll look for something the right size, or wait for the eBay seller to "open" his shop.

Ha! I just spotted a HI-FI TUNING GOLD PLATED SILVER CERAMIC FUSE 13 AMP (FOR UK MAINS PLUG) for only £34.93 "Your incoming mains signal is only as good as the weakest link. You’ve made a considerable investment in all of your components, cables and power cords, and all of the incoming power goes though a cheap fuse. These cheap, glass-body fuses are a "weak link" in your signal path." A Paul Clough has even given a review: "as soon as i played a cd i could notice a substantial difference, I was impressed, after 4 days the difference was amazing in every way openness, tighter bass, better control of the music in every aspect"

Sounds like a cheap ripoff of Russ Andrews!

F.Me! £70 for a 13A fuse, and 23 reviews giving it 5 stars. Is there anyone stupid enough to buy these things? Sadly, I suspect there is.

Why do you think 13A is too high?

Have you considered why the Shuko socket "cannot be connected direct to the 32 amp ring main"?

The issue is the lack of *fault protection* (not overload protection) for the appliance plugged into it - or more correctly for the flex connected to the appliance.

In typical installations where Schuko sockets would be used, they would be fed from small radial circuits protected by a 16A MCB. The MCB would protect the circuit itself from overload (i.e. big appliances plugged into every socket), and also give fault protection for not only the circuit (e.g. nail through a circuit cable), but also the appliance flex (e.g. someone crushing it and causing a short).

When you connect the socket to your 32A circuit, the MCB will still give overload protection and fault protection to the circuit cables, but it won't necessarily be able to offer fault protection for the appliance flex (which might be a skimpy 0.5mm^2 conductor on a small appliance). That is the main reason for needing the fused plug.

Probably. The actual current draw will depend a bit on the local voltage. For UK marketed devices with a heating element, many will quote a power assuming the supply is actually 240V - so the power could be a bit more or less depending on what your actual supply voltage is. (if yours is not a UK appliance, that power figure might be quoted at 220V)

Or, just leave the 13A one in place since it will do what it needs to do just fine (and it is already a tighter protection than that provided by the 16A MCB that it might expect sat in a German kitchen for example)

If you want to check for yourself, do an adiabatic check for the flex:

That would give you a prospective short circuit current of 230 / 1.51 =

So the only question is, could that "3A" flex take that 152A for long enough to blow the fuse before bursting into flames etc?

Plug the numbers in and get the minimum CSA of copper required in the flex to survive: s = sqrt( 152^2 * 0.1 ) / 115 = 0.41 mm^2

(that is the reason many small appliances only have 6' long flexes - it keeps the resistance low enough to get enough fault current to trip the protective device "instantly")

Ah, the golden ear brigade.

I recall seeing an article about replacing the capacitors in an audio amp with new ones with some sort of go-faster stripe.

It took the writer a couple of hours to do the job, and then he compared listening to it using music he'd listened to before beginning the work.

Honestly. He allegedly genuinely believed he could accurately recall sounds heard a couple of hours earlier, sufficiently to claim 'a vast improvement'. Marketing at its silliest.

I can recall a BBC demonstration where we were told to listen to a piece of music played over ten pairs of loudspeakers, writing down quick notes of our impressions. There were wildly different ones, for example the same model of drive unit without baffle, with a baffle, and in a sealed enclosure.

Then the curtain was pulled back and we counted... nine pairs of speakers. We were invited to guess which 'two' pairs we had heard were actually the same pair, and of course none of us got it right. This was around fifty years ago, when my ears still worked fairly well.

snipped-for-privacy@aolbin.com wrote in news: snipped-for-privacy@mid.individual.net:

Yes, I see your point although I'd probably dismiss that as simple seller ignorance rather than evidence of a substandard product. That said, if the BS spec doesn't allow for time lag fuses<?> then who knows what these items contain. BS1362 fuses are high breaking (rupturing) capacity (HRC) and are sand filled to help achieve this, these may not and you wont know unless you are happy to pop one of these expensive items open to check. Making a true HRC time delay fuse in that size of package may be problematic. If however you are aware of the limitiations that such a non-standard fuse may have and you take precautions to avoid circumstances where they might come about then you are being risk aware and sensible. One might be that if they are not HRC and encounter a momentary dead short (say cable cut) then they may still pass a leakage current to an apparently dead appliance. Mitigate this by treating any equipment or damaged cable as live until disconnected at the plug.

Although you say their paypal isn't working, their card system appears to be ok, would you prefer not to use that? Perhaps a browser issue if you're not seeing that?

This one came up on my search too, only 2 fuses, marginally more expensive and a nominal postage charge rather than free at the other place:

Yes, let's not go there, too funny.

Yes, in more ways than one ...

It sounds like a 7 amp fuse would be just fine for a coffee maker used intermittently.

The question was asked hypothetically out of interest as I don't expect reducing the wattage of the fuse will make any practical difference for the reason you state.

My understanding is the unit being factory fitted with a Schuko socket means if is safe to fuse at 16 amps. The lead on a coffee maker is more substantial than some other appliances. For the UK this would translate to 13 amps in a fused spur. All I thought was that derating the socket would be even safer, in the same way that I would prefer a

From what Joe says, I suspect 7 amps would be fine but I'll stick with

I have a 7 amp fuse which is a true collectors' item and investment opportunity. Offers over £100 please.

Instant coffee :)

But it work in an electric log splitter? Maybe the humming noise has tighter bass and more openness?

In some cases that would make sense if you were also trying to protect against overload. So if you were choosing a fuse for a cheaply made 4 ways extension lead, a 10A might be a better choice.

For a single appliance where the current demand can't be increased by user choice or error, it is not really (IMHO) necessary.

If you look at the fusing time characteristics of a BS1362 fuses, the tolerances are quite wide - with lines given for lower and upper bounds:

A 3A will take getting on for 5A to blow - but the current difference between blowing after many minuets, and a fraction of a second is very narrow. I don't have a curve for a 7A one, but chances are that will take 10A for a long duration. (although may run hot at that current)

Thanks. I should have said 'amperage' not 'wattage'. Probably more through superstition than proper science, I think I'll stick with 10 amps unless this causes problems.