Aqualisa Digital Quartz - Electrical Connection

[JohnW2]

Oh. didn't see that. Unfortunately seem to have found one that may not demand a fuse.

Maybe wishful thinking, but could this possibly be a sign that a least some of the manufacturers are coming partially 'to their senses'?

It would certainly be interesting to see what the non-English instructions say in the case of fans whose English instructions do call for a 3A fuse - since, as winston has been saying, that would not really be possible outside of the UK.

Kind Regards, John

 

[JohnW2]

That's a partial answer, with which I agree, but what about the dependability? We don't know the repeated breaking capacity of the thermal fuse (if resettable).

It may just be due to lack of experience/exposure, but I have personally never come across one of these small extractor fans that has a resettable one - and, as per experiments recently reported here, the non-resettable ones operate at currents far far lower than would blow any fuse.

Kind Regards, John

 

[ban-all-sheds]

Hands up anybody who thinks that established European electrical appliance manufacturers make products which are only safe in the 3 countries where fusing down to 3A is possible.

 

[stillp]

It may just be due to lack of experience/exposure, but I have personally never come across one of these small extractor fans that has a resettable one - and, as per experiments recently reported here, the non-resettable ones operate at currents far far lower than would blow any fuse.

Kind Regards, John

OK, I bow to your greater experience.

 

[stillp]

Hands up anybody who thinks that established European electrical appliance manufacturers make products which are only safe in the 3 countries where fusing down to 3A is possible.

Not me BAS, I'm not only talking about safety.

 

[JohnW2]

OK, I bow to your greater experience.

That's not really appropriate, since I prefaced my comment with an acknowledgement of the fact that my experience is very limited (primarily to Manrose products and a few 'own brand' ones).

All I can say is that I have personally never seen one of these small extractor fans with any sort of 'reset button' (and 'auto-resetting would probably not really be appropriate). Has anyone else seen any such thing?

Kind Regards, John

 

[JohnW2]

Not me BAS, I'm not only talking about safety.

You'ree not. However, as I've said, I'm not convinced that there is really anything else you can talk about which is relevant to the presence/absence of a 3A fuse. Certainly when a non-resettable thermal fuse is present (which has been the case with all the few that I have examined), that device would presumably operate before even a 0.3A fuse would blow - so a fuse would seemingly make no difference to anything.

Kind Regards, John

 

[stillp]

that device would presumably operate before even a 0.3A fuse would blow

What about the breaking capacity?

 

[JohnW2]

What about the breaking capacity?

I think you're rather scraping the barrel. About the only way in which one of these fans can go wrong (in an 'overload', rather than 'fault', sense) would be by the motor jamming. It has been recently shown that, under such circumstances, the rise in current is very modest (far too little to cause any realistic OPD to operate), and the thermal fuse would fairly quickly operate, long before the temperature rise would be anything like high enough to present a fire risk.

'Breaking capacity' would really only become relevant in the case of a true 'fault' (i.e. a 'short'), in which case the circuit's OPD (usually 6A or 5A) would operate, as usual. I think you would be very hard pressed to think of any realistic real-world scenario (in relation to a small extractor fan with a thermal fuse) in which a 3A fuse would operate appreciably quicker than the circuit's OPD.

I think we have already agreed that 'incidents' involving these products must be exceedingly rare (if they ever happen), even when the circuit is 'only' protected by a 16A OPD (which will be the case in many countries). That being the case, the chances of a scenario arising in which such an incident did occur, but in a situation in which a 3A fuse would operate, but the circuit's (6A or 5A) OPD would not, would surely be 'exceedingly exceedingly' rare/unlikely, wouldn't it?

Kind Regards, John

 

[stillp]

It would, if you're only considering small shaded-pole motors such as fans.

 

[stillp]

I think you're rather scraping the barrel.

No, I'm considering the 'unknown unknowns'!

 

[JohnW2]

It would, if you're only considering small shaded-pole motors such as fans.

This whole discussion is about manufacturers' requirements for a 3A fuse in relation to a small domestic extractor fan fed from a circuit with a 6A or 5A OPD.

Are we therefore agreed (in relation to the matter under discussion)?

Even though the true risks (of not doing it) would still be exceedingly small, I would imagine that most people would feel it appropriate to 'fuse down' (probably to 3A) if the fan were (pretty unusually) being supplied from, say, a 32A circuit.

Kind Regards, John

 

[JohnW2]

No, I'm considering the 'unknown unknowns'!

I don't think they are particularly 'unknown'. My personal experience is obviously very limited, and I doubt whether any statistics are available, but I think it probably is effectively 'known' that serious incidents (primarily 'bursting into flames') with small extractor fans are (almost) non-existent, despite countless millions of these things being in service, many in countries in which greater protection than a 16A OPD is not normally achievable.

Kind Regards, John

 

[stillp]

This whole discussion is about manufacturers' requirements for a 3A fuse in relation to a small domestic extractor fan fed from a circuit with a 6A or 5A OPD.

I thought it had broadened to the general issue of whether manufacturers are or are not entitled to specify fusing down for their products.

most people would feel it appropriate to 'fuse down' (probably to 3A) if the fan were (pretty unusually) being supplied from, say, a 32A circuit.

I don't think it is very unusual for people to supply an cooker hood from a 32A cooker circuit. Most people would fuse down, but kitchen fitters...

 

[stillp]

I would agree that serious incidents occurring at small extractor fans are very rare. My reference to 'unknown unknowns' was in consideration of things other than small fans.

in countries in which greater protection than a 16A OPD is not normally achievable.

Greater protection is always achievable, e.g. with the enclosed fuse units available in some countries, or by using a lower-rated MCB.