Reputable source in EU/germany for multimeter fuses?

[mwb1100]

welectron.com has the Bussman 440mA 1000V HRC fuse (10 x 35mm), IR 10kA for 9.50 EUR.  I believe they ship within Germany for free.

I'd be very surprised that that fuse's specs didn't match the Agilent specs exactly.

  - https://www.welectron.com/Cooper-Bussmann-DMM-B-44-100-R-HRC-Fuse-044A-1000V

[tooki]

The one you link to is the wrong size(..)

Not only size is different but also voltage, current rating and a bunch of other points of specification. My post was to show OP that one can buy a 500mA range fuse that can deal with 400VAC and 100kA environment (and most likely higher i2t), for €1. It was hard to guess from our 1kV capacitor bank expert posts what he really needs. It seems even that fuse is overkill for his "repair work of some appliances up tp 230V AC" needs. "Repair work of appliances" is CAT II and he won't find voltages exceeding 250V in there.

And what does that information accomplish, since such a fuse cannot be used since it physically will not fit?!? 

[tooki]

welectron.com has the Bussman 440mA 1000V HRC fuse (10 x 35mm), IR 10kA for 9.50 EUR.  I believe they ship within Germany for free.

I'd be very surprised that that fuse's specs didn't match the Agilent specs exactly.

  - https://www.welectron.com/Cooper-Bussmann-DMM-B-44-100-R-HRC-Fuse-044A-1000V

Despite showing the Bussmann and saying that in the heading, the specs and datasheet indicate it’s the SIBA fuse, which is what Agilent/Keysight ship with from the factory.

The specs aren’t 100% identical between brands (the SIBA fuses have a significantly higher interrupting rating than the Bussmann and Littelfuse) but all the same I’d consider them to be completely interchangeable.

It’s free shipping on orders above €80, so buying that fuse from Farnell is significantly cheaper in the end.

[mwb1100]

Despite showing the Bussmann and saying that in the heading, the specs and datasheet indicate it’s the SIBA fuse, which is what Agilent/Keysight ship with from the factory.

The datasheet link in the welectron page is for SIBA, but it not for the SIBA  50-210-06.  It's for the SIBA 7017240 series (the SIBA fuse the welectron catalogs).  I figure it's just an error by welectron.

The specs aren’t 100% identical between brands (the SIBA fuses have a significantly higher interrupting rating than the Bussmann and Littelfuse) but all the same I’d consider them to be completely interchangeable.

You right about the interrupt rating.  The Bussman fuse IR is 10kA, the SIBA IR is 30kA (from page 24 of this datasheet).  I am surprised by that difference, but not as surprised as I thought I'd be.

[tooki]

Despite showing the Bussmann and saying that in the heading, the specs and datasheet indicate it’s the SIBA fuse, which is what Agilent/Keysight ship with from the factory.

The datasheet link in the welectron page is for SIBA, but it not for the SIBA  50-210-06.  It's for the SIBA 7017240 series (the SIBA fuse the welectron catalogs).  I figure it's just an error by welectron.

Oh, you’re right. I looked at it on my phone before and I guess I didn’t scroll around enough. On a larger display it’s clear that the page is shared by three different fuse types.

[nightfire]

The datasheet link in the welectron page is for SIBA, but it not for the SIBA  50-210-06.  It's for the SIBA 7017240 series (the SIBA fuse the welectron catalogs).  I figure it's just an error by welectron.

You right about the interrupt rating.  The Bussman fuse IR is 10kA, the SIBA IR is 30kA (from page 24 of this datasheet).  I am surprised by that difference, but not as surprised as I thought I'd be.

To put that in perspective: Environments that can and will all of a sudden spit >1000 Amps at you are usually environments where one does not simple puts a multimeter in series with some circuit to measure Amps- mainly because the wires have the diameter of the whole multimeter ;-)

Rule of thumb, that I have memorized whilst learning about short circuits calculations: It does not matter how beefy your transformer is, after 3 meter of 1.5mm² cable (standard installation size in germany, rated 16A permanent load), you can have a maximum of roughly 2000 A short circuit power.
So, an  interrupt rating of 10 kA is fine for me.

Question here would be, if Bussmann deliberately rates the fuse lower than it could perform, so that even old and aged equipment will still perform to spec?
(Remembering possible military contracts etc. in the US)

[py-bb]

ebay, Chinese sellers have all the specific VOM fuses.

Alternative is Amazon

You know better than to recommend either of those sites. Who knows what kind of crap counterfeit fuse you might get. Even if it’s not relevant for the OP, if they ever sell or give away that meter, the new owner might not know it has a potentially unsafe fuse in it. The OP asked for reputable sources and you list the most disreputable ones possible… 

IME the fuses usually come in packs of 10 - why not test one of them? I do this because someone once freaked me out with rumours to this effect but fuses (at least easy values < 750v and < 20A) are not exactly difficult devices - it's right up there with a knock-off pencil - it's still a pencil!

[Alti]

To put that in perspective: Environments that can and will all of a sudden spit >1000 Amps at you are usually environments where one does not simple puts a multimeter in series with some circuit to measure Amps- mainly because the wires have the diameter of the whole multimeter ;-)

The fuse is there not when you measure current in series with some circuit but rather what happens afterwards, when you stick leads into a low impedance mains socket, when still in ammeter setup.

[py-bb]

Also with the 1000 amps thing that will blow the hell out of the fuse, as long as the voltage is <= fuse rating, you're good.

For example a 250v fuse means "if it blows it will block <= 250v (absolute)" - if you put say 2.5kv there that'd just arc the gap and it's possible the fuse is no longer a fuse and conducting quite happily.

So with the 1000 amp thing - this example presents no problem AS LONG AS the voltage rating is within that of the fuse.

[floobydust]

Also with the 1000 amps thing that will blow the hell out of the fuse, as long as the voltage is <= fuse rating, you're good.

For example a 250v fuse means "if it blows it will block <= 250v (absolute)" - if you put say 2.5kv there that'd just arc the gap and it's possible the fuse is no longer a fuse and conducting quite happily.

So with the 1000 amp thing - this example presents no problem AS LONG AS the voltage rating is within that of the fuse.

You are wrong, where are you getting this from?
Look at the fuse safety standards, UL 248 the test jig is set up "short circuit current in rms symmetrical amperes equal to the interrupting rating of the fuse to be tested."
Typical lowest rating is 10kA and they do test to that high current (bigger fuses to 200kA), with series inductors, inducing an arc inside the fuse to 3kV. It's all about taking the arc.
The source test voltage I think is the fuse's RMS rating, so 1,000VAC.

"The fuse shall operate and permanently clear the circuit without damage to the components of the complete fuse within the following parameters:
a) there shall be no re-establishment of current. If evidence of a tendency to restrike is noted, application of the recovery voltage shall be continued for 60 s past the time of restrike;
b) the fuse shall not emit molten metal;
c) no external soldered connections shall melt;
d) the fuse shall not exhibit movement nor deformation of either or both end caps that would result in more than 3.2 mm (0.125 in) increase in overall length;
e) there shall be no holes in the fuse as a result of this test;
f) the fuse body may discolor but shall be readily identifiable for replacement purposes;
g) for fuses with glass or ceramic bodies, cracking of the body is permissible provided that the fuse remains in one piece, without loss of filler, prior to removal from the holder or test rig; and
h) for the threshold test, fuses shall clear in the first half cycle after closing."

[py-bb]

Also with the 1000 amps thing that will blow the hell out of the fuse, as long as the voltage is <= fuse rating, you're good.

For example a 250v fuse means "if it blows it will block <= 250v (absolute)" - if you put say 2.5kv there that'd just arc the gap and it's possible the fuse is no longer a fuse and conducting quite happily.

So with the 1000 amp thing - this example presents no problem AS LONG AS the voltage rating is within that of the fuse.

You are wrong, where are you getting this from?
Look at the fuse safety standards, UL 248 the test jig is set up "short circuit current in rms symmetrical amperes equal to the interrupting rating of the fuse to be tested."
Typical lowest rating is 10kA and they do test to that high current (bigger fuses to 200kA), with series inductors, inducing an arc inside the fuse to 3kV. It's all about taking the arc.
The source test voltage I think is the fuse's RMS rating, so 1,000VAC.

"The fuse shall operate and permanently clear the circuit without damage to the components of the complete fuse within the following parameters:
a) there shall be no re-establishment of current. If evidence of a tendency to restrike is noted, application of the recovery voltage shall be continued for 60 s past the time of restrike;
b) the fuse shall not emit molten metal;
c) no external soldered connections shall melt;
d) the fuse shall not exhibit movement nor deformation of either or both end caps that would result in more than 3.2 mm (0.125 in) increase in overall length;
e) there shall be no holes in the fuse as a result of this test;
f) the fuse body may discolor but shall be readily identifiable for replacement purposes;
g) for fuses with glass or ceramic bodies, cracking of the body is permissible provided that the fuse remains in one piece, without loss of filler, prior to removal from the holder or test rig; and
h) for the threshold test, fuses shall clear in the first half cycle after closing."

The first sentence seems to be wrong:

Fuses have both a current and voltage rating. They only guarantee they will cut the circuit when the (absolute) voltage is less than their rating. Incase you have not encountered this wording a 250v fuse will be OK with -250v or +250 across it, but not -300v or +300v.

You must obey BOTH if you want protection.

I will restate it again (even though I think it was perfectly clear) - enough volts will arc at some point. If you put say 100kv across it (so a really big static shock) - it's just going to arc the gap in the fuse. If there's enough current this can ionise the gas in there and you get a consistent arc.

Fuse voltage ratings are meaningful and important as I said.

[nightfire]

Correct. Fuse voltage ratings are important, and having a very high-voltage spike can certainly do havoc.
In real applications, a slightly higher voltage than rated voltage usually causes no direct immediate harm, but causes higher heat dissipation than the fuse originally was designed for.
And this can lead to some other significant issues in the surrounding.

[floobydust]

What is "with the 1000 amps thing" ?  Fault currents on mains can be very high. I notice UL is 10kA basic yet IEC is 1kA, so fuse standards are different and this might be an issue.

[py-bb]

What is "with the 1000 amps thing" ?  Fault currents on mains can be very high. I notice UL is 10kA basic yet IEC is 1kA, so fuse standards are different and this might be an issue.

People often think of something that could provide say 1000A (at a low voltage) as inherently dangerous because of 1000 amps "being available" - I used it as an example to show that "even if your supply could provide 1000 amps as long as the fuse's voltage rating is >= supply voltage" the fuse will (safely) blow and break the circuit.

Contrast with many thousands of volts available on say a 250v fuse - it blows and then it'll just arc across the gap, the fuse is not guaranteed to be able to break this circuit (increase voltage as necessary to prove point)

[tooki]

Contrast with many thousands of volts available on say a 250v fuse - it blows and then it'll just arc across the gap, the fuse is not guaranteed to be able to break this circuit (increase voltage as necessary to prove point)

Did you mean to write thousands of amps?

[Alti]

Right, fuses have their envelope of operating parameters and work in limited range. The standard or datasheet does not give the shape of the envelope but just points inside of safe zone.

BTW, any interesting YT with some spectacular kills?
I remember I have seen a training video of a 50kA fuse (IEC60269?) that was purposely blown in 100kA or 200kA circuit just to show how to ruin one's day by exceeding envelope. I just cannot find this YT..

[nightfire]

Contrast with many thousands of volts available on say a 250v fuse - it blows and then it'll just arc across the gap, the fuse is not guaranteed to be able to break this circuit (increase voltage as necessary to prove point)

Did you mean to write thousands of amps?

I would think py-bb meant Volts, as the Volts ultimately are driving the Amps... Also you need higher distance/clearing between the electrodes/poles of a fuse to really be able to break down the arc that is created for a moment.
There is a good reason why the 1000V fuses in a multimeter are longer than the small glass 5x20mm fuse foir household applications...

[floobydust]

It would be nice to up the technology so that a 5x20mm fuse could be used in multimeters (above 250VAC) instead of the huge 10x38mm parts. I thought of the exploding fuses used in electric utility distribution transformer primary protection, like 25kV lol. Those are really loud like a gunshot.

I think not much in fuse technology has improved in many decades, and here is Eaton asking $75 for the same old fuse a step above Henry T Bussmann's 1919 patents.

[KaneTW]

The short circuit current past NH 100A fuses is limited to less than 10kA and additionally limited by the meter and other fuses. Realistically it will be less than 6kA in the main panel and less than 2kA at any outlet.

German residential panels rarely (never?) have fuses above 100A.

[Alti]

It would be nice to up the technology so that a 5x20mm fuse could be used in multimeters (above 250VAC) instead of the huge 10x38mm parts.

How many people out there are willing to "I measure leakage currents and such, or the power consumption of E27 lightbulbs with LEDs- here we are talking about mA." on a circuit that goes beyond 250V? I am afraid you are the only one. There are no markets for 400V or 500V LEDs with mA leakage. BTW, clamp meters go well below mA range and there are those optimized for low ranges, those for RCCB leakage tests.

[tooki]

Contrast with many thousands of volts available on say a 250v fuse - it blows and then it'll just arc across the gap, the fuse is not guaranteed to be able to break this circuit (increase voltage as necessary to prove point)

Did you mean to write thousands of amps?

I would think py-bb meant Volts, as the Volts ultimately are driving the Amps... Also you need higher distance/clearing between the electrodes/poles of a fuse to really be able to break down the arc that is created for a moment.
There is a good reason why the 1000V fuses in a multimeter are longer than the small glass 5x20mm fuse foir household applications...

Yyyyeah…. But I don’t see what your reply has to do with mine.

My point was that the sentence “Contrast with many thousands of volts available on say a 250v fuse…” makes no sense at all. Volts are not “available” (amps are available). Volts are applied.

[nightfire]

Ah yes- in this regard, correct.
Volts are applied.

The thing is, that depending on the amount of Volts there is a distance that has to be kept so that an arc can not happen. Filler materials as sand help extinguishing an arc, but nonetheless also the contacts of the fuse are to be placed at that same distance, otherwise an arc will form at this point if the voltage is high enough.
So it makes sense that fuses grow longer, the higher their rated voltage is.

Most multimeters that are rated for 600V use 6,3x32mm fuses, because they are long enough for this kind of voltage, and readily available.

The lower the rated voltage, the shorter the fuses can be- for example, SIBA 70 007 40  is a 5x20mm fuse, FF characteristic, and 400V with 10kA rating.
Above that, we are in the territory of  the 6,3x32mm fuses.
Also a point that bigger fuses allow for bigger contact area to the holders and bigger wire (or whatever shaped metal plates) in the inside, so potentially having a lower resistance and therefor dissipating less energy as heat.

[tooki]

Who are you telling that to? I already know all of that. I made the apparently grave error of pointing out the presence of and asking for clarification of a nonsensical comment, it wasn’t a general request for clarification on the topic.

[py-bb]

Contrast with many thousands of volts available on say a 250v fuse - it blows and then it'll just arc across the gap, the fuse is not guaranteed to be able to break this circuit (increase voltage as necessary to prove point)

Did you mean to write thousands of amps?

I would think py-bb meant Volts, as the Volts ultimately are driving the Amps... Also you need higher distance/clearing between the electrodes/poles of a fuse to really be able to break down the arc that is created for a moment.
There is a good reason why the 1000V fuses in a multimeter are longer than the small glass 5x20mm fuse foir household applications...

Yyyyeah…. But I don’t see what your reply has to do with mine.

My point was that the sentence “Contrast with many thousands of volts available on say a 250v fuse…” makes no sense at all. Volts are not “available” (amps are available). Volts are applied.

So you asked a question "what was that 1000s of volts bit about", I replied, as for the rest, let's read it again:

Okay so when we speak of thousands of volts available imagine a special high voltage power supply - if you apply that a 250v fuse one of three things happens (unless by thousands of volts you mean so high it just arcs across everything - which would be many 10s or 100s of thousands)

We may say a 9v battery has "9v available [across the terminals]" - it's maybe a British English thing but it's in common parlance.

Anyway the three cases:

1) Absolutely nothing - current is below the fuse's rating, there's a circuit, all is well
2) Fuse pops creating a gap in the fuse wire - and the voltage isn't enough to arc across that gap - the "lucky" case, the fuse has done its job, even though you've abused it by going beyond the ratings
3) Fuse pops but the voltage is high enough it just arcs across the gap so even though the fuse is blown it's still conducting

Apparently it (proper high voltages) can ionise the air (like a welding arc) and sustain this but I don't deal with the area.

Make sense now? It's the same case wrapped up differently: You must pay attention to fuse voltage ratings!


If the fuse were rated for the voltage the manufacturer's are "guaranteeing that it should" be able to break the circuit at that voltage or less - so our 250v fuse would be fine in in a 100v system or whatever. It would be inadequate in a 600v system - it may still work and break the circuit but you can't count on this and should get one rated for 600v

[tooki]

Contrast with many thousands of volts available on say a 250v fuse - it blows and then it'll just arc across the gap, the fuse is not guaranteed to be able to break this circuit (increase voltage as necessary to prove point)

Did you mean to write thousands of amps?

I would think py-bb meant Volts, as the Volts ultimately are driving the Amps... Also you need higher distance/clearing between the electrodes/poles of a fuse to really be able to break down the arc that is created for a moment.
There is a good reason why the 1000V fuses in a multimeter are longer than the small glass 5x20mm fuse foir household applications...

Yyyyeah…. But I don’t see what your reply has to do with mine.

My point was that the sentence “Contrast with many thousands of volts available on say a 250v fuse…” makes no sense at all. Volts are not “available” (amps are available). Volts are applied.

So you asked a question "what was that 1000s of volts bit about", I replied, as for the rest, let's read it again:
…

I asked if you meant amps instead of volts, since your sentence didn’t make sense. OTHER people replied, but YOU didn’t reply until now.

We may say a 9v battery has "9v available [across the terminals]" - it's maybe a British English thing but it's in common parlance.

I categorically reject your claim that volts are “available” is common usage, British or otherwise. We have enough British members (and many more native speakers of other dialects of English, like me) here that if it were common, we’d see it here all the time.

A voltage source provides or supplies a voltage, and a voltage is applied to something else.

You can say “I have 5, 9, and 12V available” to mean that you have those voltage sources available. But the source itself can’t have a voltage “available”.

But it makes even less sense in your usage that I commented on: a voltage “available” at a load!