Short-lived Dissmann Fuse.

[paul8f]

"Dissmann" . . . anybody ever hear of this brand-name in the cartridge-fuse world?



This 3A plug-top fuse blew after just 2 uses of a 500w Milk heater/frother. The frother is a Swan SK33020BLKN, and is rated at 220-240Vac @50Hz.

I've replaced the fuse, and the unit has worked flawlessly a good few times now. An in-line power meter shows it drawing about 2.2 Amps at 230V.

It was probably just a once-off, but in general is Dissmann a common brand, or could it be a heating-element issue? (Dissmann sounds like a chinesium version of Bussmann.)

[coromonadalix]

https://ittsb.eu/forum/index.php?topic=1428.0

redirect here
https://www.ittsb.eu/forum/index.php?topic=1428.msg3432#msg3432

a very similar eevblog look a like powered site loll

[Gyro]

Dissmann does indeed sound like a Chinese 'modification' of Bussmann, however they do appear to be a Chinese fuse manufacturer offering lots of fuse types (I'd never heard of them either)...

https://www.dissmann-fuse.com/

You still face the same dilemma however - are they fake Dissmann fuses? 

If it's a fake BS1362 fuse, then it may well be missing its silica sand filling, this seems to be a common sign. Carefully breaking open one of the dead fuses would reveal this. An empty fuse would potentially have a shorter thermal time constant too, making it more likely to fail on turn-on surges (assuming that the wire element is anything like the right material and thickness).

Heating element issues normally show up as a short between the element and outer metal sheath, which would immediately blow the RCD (assuming your house has them fitted).

[Seekonk]

It is still a mechanical assembly.  A friend asked me to look at an intermittent motorcycle problem. It came down to a bad fuse much the same construction as yours.  It looked perfectly good and the ends did not spin.  It made internal contact at times and not others. At the speed thy make these it is hard to imagine there aren't more issues.

[paul8f]

Just to update you guys...
On a crude balance-scales there was no real difference in weight between the blown Dissmann and an old SEM 3A fuse, so it appears as if the fuse-filling is at least present and the correct density. However that doesn't mean it's the correct grade for the internal 3A element-wire. The end-caps of the Dissmann are solid (no rotation or looseness, or noise when shook, etc).

When I've more time it might be interesting to to an "autopsy" on the fuse! Anybody know how to do it and what I should be looking for?

I doubt a power-surge could have caused a "slow-blow" fuse like this to pop, so bad luck, a cheap fuse, or a non-genuine part are the most likely explanations I'm guessing.

Thanks for the replies.

EDIT:  What's a little alarming, is the fact that the current-rating is clearly stamped on the fuse-body (3A), but there's no sign of a voltage rating (250 Vac etc). - Am I correct in saying that displaying the voltage rating is required by the BS1362 standard, but not by the Singapore SS167?

[Gyro]

I believe the voltage rating, together with breaking capacity are specified in BS1362*, so don't need to be marked separately - I've just been through a handful in the kitchen and non has a voltage marking.

I was going to comment that the 'Lead Free' marking looked a bit suspicious but I actually came across a Dissmann fuse in the bunch and it does indeed say Lead Free - It is the only one that does though, I wasn't aware that the fuse elements were soldered.

In terms of fuse autopsy, with the aid of a couple of pairs of pliers, it should be possible to twist off one of the end caps. There is a high chance that you will crush the ceramic tube so watch your eyes. The sand is special silica so should have a white appearance with uniform grain size and possibly round grains. It certainly shouldn't look like beach sand.


P.S.

I doubt a power-surge could have caused a "slow-blow" fuse like this to pop, so bad luck, a cheap fuse, or a non-genuine part are the most likely explanations I'm guessing.

BS1362 fuses are actually classed as Fast blow. You could have just been unlucky though, fuses are never going to be more than batch tested, probably very large batches at that.

*BS1362 specifies...

   "• the rated voltage;
    • the rated currents;
    • the rated power loss;
    • the time/current zones and conventional currents;
    • the rated breaking capacity; and
    • the dimensions."

... if you fancy forking out £220 for it!    https://knowledge.bsigroup.com/products/general-purpose-fuse-links-for-domestic-and-similar-purposes-primarily-for-use-in-plugs-specification