Replace Multimeter Fuse

[ruibca]

Hello all,

I need to replace both fuses on a Hioki DT4282 which requires a 11A 1000V 10.3 x 38mm ceramic fuse and a 630mA 1000V 10.3 x 38mm ceramic fuse. I can only find the same make (HOLLY) on peaktech and they only seem to do up to 10A. Is is ok to use a 10A fuse instead of 11A?

Many thanks,

Rui

[wraper]

It's a specialized multimeter fuse and it does not necessarily need to be ceramic. For example you could use Busmann DMM-B-11A which is also sold as Fluke F-11A. Or Littlefuse 0FLU011.T, Siba 50 199 06.11, just don't buy it from dodgy places, ebay is full of counterfeits. 10A fuse most likely is simply a usual fast acting fuse which is not nearly as fast as multimeter fuse.

[ruibca]

Thank you wrapper. PeakTech seem to be a reputable company. I've ordered the 630mA 1000v from their "Fuses for Multimeters" section (https://peaktech-rce.com/en/fuses-for-multimeters/543-peaktech-7520-ceramic-fuse-ff-630ma-1000v-103x38mm-10-pieces.html).

What you're saying is that it's best not to use the 10A fuse if the meter asks for 11A? Even if on the outside of the meter is says 10A FUSED.

[ledtester]

What is the fuse protecting?

Seems like it is just protecting the 10A current measurement input. So using a lower amperage fuse is fine -- it will only reduce the maximum current you can measure.

[wraper]

What is the fuse protecting?

Seems like it is just protecting the 10A current measurement input. So using a lower amperage fuse is fine -- it will only reduce the maximum current you can measure.

Nope, as I said multimeter fuses are much faster than usual fuses.

What you're saying is that it's best not to use the 10A fuse if the meter asks for 11A? Even if on the outside of the meter is says 10A FUSED.

It's multimeter nominal input rating, not fuse rating. Again, multimeter fuses are different from usual fuses, even if they are HRC type.

[ruibca]

Seems like it is just protecting the 10A current measurement input.

Yes, it's just for the A input. The mA and µA have a 630mA socket (image attached).

It's multimeter nominal input rating, not fuse rating. Again, multimeter fuses are different from usual fuses, even if they are HRC type.

I don't mind if it can only handle 9A instead of 10A as I use it exclusively for small electronics projects. I just want to make sure it's safe to do so (for me and the multimeter). The ones I was looking into seem to be specific for multimeters and seem to be good quality - the same that came with the multimeter - and a good price for 10 pieces (https://peaktech-rce.com/en/fuses-for-multimeters/545-peaktech-7530-ceramic-fuse-ff-10a-1000v-103x38mm-10-pieces.html). Unfortunately they don't seem to do 11A.

[Jwillis]

You could try https://www.tester.co.uk/catalogsearch/result/?q=fuse&p=2  for the UK  .They have the  Fluke 803293 Fuse - A:11A (F), V:1000V, IR:20kA, 10.3x38.1 mm . When I checked they had one in stock.

[eblc1388]

The question: "What is the fuse protecting?" is really an important one, as it determine what type of fuse is to be used.

For the fuse in series with the 10A current range, its main purpose is to protect the user and cut off the current when user connects the test leads across a voltage source by mistake. Its secondary function is to interrupt the current should a dumb user tried to pass excess current through the meter continously.

While the fault current in homes are usually limited, one can expect current of thousands of amps if the meter is used wrongly on system busbar.  This mistake would easily means live or dead for the user. Thus the critical data to check on the replacement fuse is fault interrupting capacity, expressed in KA. The replacement fuse should have the same or higher KA than the original. Chances are they are already being the highest KA type available.

With that done, then the voltage and current rating come into consideration.

[ruibca]

Thank you eblc1388. The interrupting capacity is a useful bit of information. I was wondering what that was. On the original fuse there are values for AC and DC: l1=50KA AC and l1=30KA DC.
On the new one there's only one value: l1=50kA (image attached - old and new fuse). Not sure if the 50kA applies for both AC and DC in this case. But like I mentioned, I'm not planning to measure ac current any time soon. However, as I understand 4S LiPo batteries (14.8V) can put out a lot of current as well (possibly more than 10A).
So back to my original question, can I assume that, based on everything else being the same, it's safe to use a 10A fuse instead of a11A fuse? Many thanks.

[Per Hansson]

The important thing is that the fuse is fast so it interrupts before the tracks and semiconductors in the multi meter explodes.
This is designated by the "diode" icon on the fuse which is for the "aR" rating, which means semiconductor fuse.
That takes care of the protection of the multi meter and is also explained by Dave in the video linked below.
But the more important designation is breaking capacity as has already been discussed in this thread.
So that the fuse is also able to quench an plasma arc formed if you by mistake short out a high energy circuit.
So these are the two most important factors when selecting a multi meter fuse, not its ampere rating...

[ruibca]

Brilliant! I guess that sums up all the parameters in a fuse. Thank you for the insight Per Hansson and everyone else for their input.
This is my first post in this forum and I'm well impressed with the generosity!

[tooki]

The important thing is that the fuse is fast so it interrupts before the tracks and semiconductors in the multi meter explodes.
This is designated by the "diode" icon on the fuse which is for the "aR" rating, which means semiconductor fuse.
That takes care of the protection of the multi meter and is also explained by Dave in the video linked below.
But the more important designation is breaking capacity as has already been discussed in this thread.
So that the fuse is also able to quench an plasma arc formed if you by mistake short out a high energy circuit.
So these are the two most important factors when selecting a multi meter fuse, not its ampere rating...

Indeed. I have a suspicion that the oddball 440mA and 11A values (which don’t seem to exist outside of DMM fuses) are specifically to discourage people from substituting other fuse types.

[slugrustle]

There are a couple of sellers on eBay with these Hollyland HC10aR fuses in stock for about $10 USD each.  I think the eBay tip came from an amazon review of the DT4282...

I found the datasheet at http://www.hollyfuse.com/UploadFile/230925ProductDLLixin/HC10aR%20250mA-32A%20HLDL-2307-02_74.pdf.

EDIT: The fuses from eBay did not appear to be genuine.  They had no UL recognized mark and different resistance from DT4282 original fuses. I was able to buy new fuses from a local partner of Hioki by filing a repair and calibration request through a link on the webpage https://www.hioki.com/us-en/support/service.

[trinitty]

Hello guys,
I've just received an "original fuse" for Hioki DT4282 from Ebay. I don't really know if it's the real thing. Have some doubts. Can you take a look and give me your thougts ?
On the left, the blown original fuse.
On the right, Ebay fuse.
Thanks !

[BeBuLamar]

I wonder if the fuse resistance has an effect on the meter accuracy. The shunt resistor for the 10A range is very small and a little resistance from the fuse can have big impact.

[trinitty]

The fuse in the pic is the 630 ma/1000v. The 10A one, measures 0.1 ohm.

[bdunham7]

The question: "What is the fuse protecting?" is really an important one, as it determine what type of fuse is to be used.

It is an important question but you also have to know how it is achieving that goal.

The primary purpose of the fuse is to protect the user from thermal injuries from an accidental arc-flash event.  Without rehashing the entire process, an arc-flash may develop when you short out a high-energy mains power source, typically three-phase 480VAC service panels or other areas with high power connections.  The arc-flash is essentially a plasma cloud that continues to short out the source until the power is removed by an upstream protection device or the whole thing explodes or burns down.  This accident can happen if you mistakenly connect your DMM to a high-energy source with the leads in the current jacks and this is the scenario where the fuse is intended to step in and protect you from your own stupidity.

There are two places where the arc-flash is likely to start--at the tips of your probes or within the fuse itself as it blows. The arc-flash doesn't form instantly, but takes a few milliseconds to grow to the point where it continues.  If you can interrupt the fault quickly enough you will hopefully avoid the arc flash.  The fuse itself is sand-filled and designed to contain any arcs that arise within it.  However, the only way to protect the user from an arc-flash starting at the probe tips is to interrupt the current flow very quickly.  The typical 11A fuses used in Fluke and other decent DMMs has a rated "total clearing time" of 10ms at 200A.  This presumably decreases with higher currents, but the chart bottoms out at 10ms so I suppose nothing is guaranteed past that point. 

Multimeter-specific fuses are not unique regarding clearing time. There are other specialty fuses that behave similarly, such as solar protection fuses and other "fast" fuses that have a 1kV AC/DC and 10kA+ interrupt ratings.  Fuses with lower interrupt ratings are not going to perform as well regardless of their time/current curve because they will have a longer arc time.

[bdunham7]

I wonder if the fuse resistance has an effect on the meter accuracy. The shunt resistor for the 10A range is very small and a little resistance from the fuse can have big impact.

It causes a burden voltage on the circuit being tested but shouldn't affect the meters ability to measure whatever current is flowing since the meter only looks at the voltage across the shunt.

[Whales]

Hello guys,
I've just received an "original fuse" for Hioki DT4282 from Ebay. I don't really know if it's the real thing. Have some doubts. Can you take a look and give me your thougts ?
On the left, the blown original fuse.
On the right, Ebay fuse.
Thanks !

On one fuse the "630mA" and its box have the same line weight.  On the other the text is noticeably thicker than the box line.  This suggests that they have different art source files.

Still could be legit, no idea.  The letter kerning and serifs seems the same.

I'd normally recommend cutting them open to see if they have the same fill inside, but I expect you won't want to do that 

[watchmaker]

I watched Dave's video on the DMM fuses and input protection.  Enlightening.

So, are counterfeit fuses (Littlefuse or Bussman) being sold on Amazon?  The price difference between Amazon and Digikey (as well as wait time) is enormous.

I have been very naive.

THANKS!

[bdunham7]

So, are counterfeit fuses (Littlefuse or Bussman) being sold on Amazon?  The price difference between Amazon and Digikey (as well as wait time) is enormous.

Probably, but you can still find reputable places to buy them for non-stupid prices.  For the 11A 10x38 model, there are several different part numbers that Fluke used and they all look a bit different.  There's BUSS-labeled DMM-11A that appears in all my older (2000-2010s) Fluke meters, the Littelfuse FLU-11A that they are using now and an Eaton/Bussmann DMM-B-11A that I bought from Witonics but haven't seen in an actual meter yet (not that I should have...)  They all look a bit different and some of the DMM-11A units actually have the caps on a bit crooked but are not fake. 

These appear to have a list price from Fluke of $9.95, $12.62 or $21.00 depending on where you look.  You can get the latest FLU-11A from TEquipment for $8.46.  This isn't a $100 part and anyone showing you a price like that is playing some game or another. 

https://www.tequipment.net/FlukeFuses943121.html

Or Witonics on Amazon has a 5-pack of the DMM-B-11A for $20. 

https://www.amazon.com/Multimeter-DMM-11A-DMM11-Replace-Acting/dp/B07ZGW4J8C/ref=sr_1_2?dib=eyJ2IjoiMSJ9.YLFtw0Fr-MrVpUEvEyPZEneCunXodCBY4H9YuQ_RA-SAiXi9KsZ1DEkdtBnDNLJH6cPQFT7HkCeRgE9sFGTFaGkS53Zerf_t-NTC9sbh8N7DSApc5_qpYUB8mxodm7HLU-ZNH9Kuog28Aitx3mN14IdIrRzZA-VsCbFWn3qX7ANcJB9E8vQI9r03D4_i-sGKUdDApT41Sts87DF_i-dND6ZILg1WsqbU3gD82ef1Cn8.rToIo7qfKYxqPuXpFRDJ9e9FA4uajGf_LB-v-5x5eM4&dib_tag=se&keywords=fluke+fuse&m=A1UOBWSFLOXPFW&qid=1740432382&s=merchant-items&sr=1-2

I couldn't shorten that link without losing the sale price, IDK why.  It's not an affiliate link, at least not mine.

[BeBuLamar]

I wonder if the fuse resistance has an effect on the meter accuracy. The shunt resistor for the 10A range is very small and a little resistance from the fuse can have big impact.

It causes a burden voltage on the circuit being tested but shouldn't affect the meters ability to measure whatever current is flowing since the meter only looks at the voltage across the shunt.

Aha!Thank you! That's why when I use my DMM as current shunt to measure current with the scope it appears to be of higher value shunt than the specs said it is.

[inse]

It appears to me this discussion is going a little academic.
The type of fuse required depends very much on the use case of the measurement device.
Besides two CAT III/IV hand multimeters, I also own several benchtop multimeters (Keithley and HP) their input protection is a standard 5x20mm fuse.
Because those instruments are neither designed nor likely being carried into a transformer substation, thats why a standard device fuse is sufficient.
For a multimeter that is indended to be used (or cannot be excluded to be used) on high energy supply installations, a properly designed input protection is required.
So in my opinion if you solely plan to use your multimeter on the workbench, CATx rated fuses are not necessary, a standard fast blow device fuse is sufficient.
The LiPo battery you mentioned can deliver a lot of current but the voltage is low enough not to form a powerful arc.
Thats how I see it.

[BillyO]

So in my opinion if you solely plan to use your multimeter on the workbench, CATx rated fuses are not necessary, a standard fast blow device fuse is sufficient.

While I agree with this in concept, the problem is, if the meter is rated for CAT-4, like a high end Fluke, Brymen, etc.. that meter may someday get passed on to someone that will try to use on industrial switch gear by virtue of it's specifications and wind up in hospital with serious injuries.  The net-net here is, if you change the specification of the fuse, you change the specification/capability of the meter.

[BeBuLamar]

I think it's best to replace the fuses with the correct ones and be careful not to blow them again.