Replace Multimeter Fuse

[trinitty]

I took some measures and now I'm quite sure it's a fake product (acording to Holly HC10aR datasheet). Moreover the crimping rings are missing on the fake fuse.
I've found the replacings, finally at
"https://peaktech-rce.com/en/fuses-for-multimeters/543-peaktech-7520-ceramic-fuse-ff-630ma-1000v-103x38mm-10-pieces.html"
I'll buy both 630ma and 10a (there's a limit of 75 €) and if anyone is interested, just let me know.
Thanks for your help.

[BeBuLamar]

I took some measures and now I'm quite sure it's a fake product (acording to Holly HC10aR datasheet). Moreover the crimping rings are missing on the fake fuse.
I've found the replacings, finally at
"https://peaktech-rce.com/en/fuses-for-multimeters/543-peaktech-7520-ceramic-fuse-ff-630ma-1000v-103x38mm-10-pieces.html"
I'll buy both 630ma and 10a (there's a limit of 75 €) and if anyone is interested, just let me know.
Thanks for your help.

You determined that the Fuses are faked just because the dimensions are a bit difference? It could be variation in production.

[trinitty]

Yes. It could be. And yet...The datasheet shows a lenght value = 38.0+/-0.6 mm. And then the measured resistance value.
Actually for those who own Hioki DT4282, maybe they can measure their own original fuses and post their findings here, for reference. It would be appreciated.

[BeBuLamar]

Wow so someone faked a Chinese made product. So perhaps they made them in Vietnam? Also the resistance values are very close. I don't think they can be tighter tolerance than that. For the 630mA fuse the error was only -1%. The 11A fuse the error is less than -1% and Hioki stated that it can be 0.1 or less.

[trinitty]

The fuse of interest is the 630ma one. I don't know what the normal resistance value is since I don't have any other to compare with. The 11A one is the original.
So what you're telling is >1 ohm for a fuse (630ma in my case) is a normal value (knowing that the original 11A is 0.1 ohm). As for the dimensions, as far the factory is issuing  a datashett with accepted tolerances, yes I think the fuse in discussion is fake.
I don't like controversial disscusions. If you have smth of value to say and you're willing to help, please do so.
I'm simply cautious in using a questionable (IMO) product in my preciuous DMM.

[Monkeh]

Yes. It could be. And yet...The datasheet shows a lenght value = 38.0+/-0.6 mm. And then the measured resistance value.

And which measurement falls outside the range of 37.4 to 38.6mm?

~1ohm is quite normal for a fuse in that range. For example, here's a datasheet for a slightly smaller fuse used in other meters, complete with nominal resistance: https://astml.com/wp-content/uploads/2023/12/HV620-Series_1000VDC_20231223.pdf

[BeBuLamar]

The fuse of interest is the 630ma one. I don't know what the normal resistance value is since I don't have any other to compare with. The 11A one is the original.
So what you're telling is >1 ohm for a fuse (630ma in my case) is a normal value (knowing that the original 11A is 0.1 ohm). As for the dimensions, as far the factory is issuing  a datashett with accepted tolerances, yes I think the fuse in discussion is fake.
I don't like controversial disscusions. If you have smth of value to say and you're willing to help, please do so.
I'm simply cautious in using a questionable (IMO) product in my preciuous DMM.

The specs in the Hioki manual said the 630mA fuse should have 1.2Ohms resistance and the one you measured was 1.178 that's very close. And all the fuses dimension you measure is less than 38.6mm which is within specs.

[trinitty]

Yes. It could be. And yet...The datasheet shows a lenght value = 38.0+/-0.6 mm. And then the measured resistance value.

And which measurement falls outside the range of 37.4 to 38.6mm?

Yes. My mistake. I mistook the tolerance for a smaller value (0.06mm)
Thank you Monkeh. And thanks for the datasheet. Thank you all.

[Whales]

If you're certain it's a fake then crack it open and see if it has a sand-like media inside.  AFAIK all HRC fuses are filled, except fake ones, but I could be wrong.

[mwb1100]

I have seen many posts that claim that faked name brand multimeter fuses are rife on Amazon and eBay.  But I've never seen anything approaching evidence of that.  (note: I'm not talking about cheap no-name fuses which definitely have marginal to poor performance, as you'd expect).

At worst I'd expect the "fakes" to be off-the-books factory runs.  Maybe seconds/QA non-passes - but I'd be surprised.

Anyway, has anyone ever seen evidence?  Missing sand fill or a typo on the labeling?  Surely if Littelfuse multimeter fuses are being faked there would be some marked "LittleFuse"

[bdunham7]

Anyway, has anyone ever seen evidence?  Missing sand fill or a typo on the labeling?  Surely if Littelfuse multimeter fuses are being faked there would be some marked "LittleFuse"

https://www.eevblog.com/forum/testgear/fake-bussmann-multimeter-fuses-on-ebay-dmm-b-44100-r-and-dmm-b-11a/

Sort of inconclusive, but even relabeled other-brand fuses (which to me does mean "fake") may not be that bad in quality and may function close enough to normally that few will notice.  You could just order BOJACK brand fuses though--no need for fake labels.

[slugrustle]

The fuse of interest is the 630ma one. I don't know what the normal resistance value is since I don't have any other to compare with. The 11A one is the original.
So what you're telling is >1 ohm for a fuse (630ma in my case) is a normal value (knowing that the original 11A is 0.1 ohm). As for the dimensions, as far the factory is issuing  a datashett with accepted tolerances, yes I think the fuse in discussion is fake.
I don't like controversial disscusions. If you have smth of value to say and you're willing to help, please do so.
I'm simply cautious in using a questionable (IMO) product in my preciuous DMM.

I measured the original 630mA fuse in my DT4282 with a Rigol DM3068 bench DMM in 4-wire mode with two-pin Kelvin probes and got 1.089Ω.  The original 11A fuse came in at around 10mΩ.  The extra 0.1Ω in your readings is probably the resistance of your DMM test leads.  Try using rel mode to subtract the test lead resistance.

Unfortunately, the replacement 630mA fuses that I purchased on eBay have a resistance of about 334mΩ, which is not right.  They have red writing instead of blue and do not bear the UL recognized mark like the original fuses.  The 11A eBay fuses come in at 13mΩ, close to the originals, but no UL recognized mark again.  Maybe they don't bother with that mark when distributing to places other than the US...

I'm registering the meter with myHioki to see if maybe I can get fuses through Hioki directly.

I took some measures and now I'm quite sure it's a fake product (acording to Holly HC10aR datasheet). Moreover the crimping rings are missing on the fake fuse.
I've found the replacings, finally at
"https://peaktech-rce.com/en/fuses-for-multimeters/543-peaktech-7520-ceramic-fuse-ff-630ma-1000v-103x38mm-10-pieces.html"
I'll buy both 630ma and 10a (there's a limit of 75 €) and if anyone is interested, just let me know.
Thanks for your help.

The high current fuse has an 11A rating, not a 10A rating.

[cte]

I got this pack of 630 mA/1kV fuses from Distrelec, sold under the PeakTech brand, but apparently made by Holly.

[Update]: Measured resistance of 1.07 Ω and weight of one fuse is approx. 10.7 grams.

[slugrustle]

I filed a repair & calibration inquiry with Hioki using the "Contact Us" link on the webpage https://www.hioki.com/us-en/support/service.  I put N/A for company name.  Someone from ETI Energy Tools responded the next business day offering replacement fuses of both sizes for $18.70 each.

I should have tried the service request form earlier.

[watchmaker]

I looked at how to replace the fuse in the Fluke 45.  Looks like at least an hour to get the job done!

Do NOT blow that fuse.  OTOH, if I do blow it, maybe replace it with a 1 A slow blow? 

[BeBuLamar]

I looked at how to replace the fuse in the Fluke 45.  Looks like at least an hour to get the job done!

Do NOT blow that fuse.  OTOH, if I do blow it, maybe replace it with a 1 A slow blow? 

Shouldn't take an hour to replace it. Both the power supply fuse and the 100mA can be replaced without opening the case. The 10A fuse you have to open the case but it wouldn't take that long.

[Monkeh]

I filed a repair & calibration inquiry with Hioki using the "Contact Us" link on the webpage https://www.hioki.com/us-en/support/service.  I put N/A for company name.  Someone from ETI Energy Tools responded the next business day offering replacement fuses of both sizes for $18.70 each.

I should have tried the service request form earlier.

How much?

I know these are fairly specific fuses but they're not that expensive.

[watchmaker]

I looked at how to replace the fuse in the Fluke 45.  Looks like at least an hour to get the job done!

Do NOT blow that fuse.  OTOH, if I do blow it, maybe replace it with a 1 A slow blow? 

Shouldn't take an hour to replace it. Both the power supply fuse and the 100mA can be replaced without opening the case. The 10A fuse you have to open the case but it wouldn't take that long.

Talking about the DMM 4410  .4mA fuse.  That is buried deep.

[bdunham7]

Talking about the DMM 4410  .4mA fuse.  That is buried deep.

If you do have the IEC 1010 version (later, not as common) then it's just three screws, slide the chassis out of the case and you're looking right at it.  If you have the earlier non-IEC 1010 version then there is no secondary fuse for the 100mA range.  The only fuse that takes a bit of work to replace would be the one on the battery board if you have that option.

[watchmaker]

I see what happened.  The manual goes straight thru to complete disassembly after describing F2 and F5.  Since i was just looking to see what is involved, I read it quickly and did not notice the procedure you describe.

[slugrustle]

The part numbers for the Hioki DT4282 fuses are:

630mA/1000V: 600391390
11A/1000V: 600391380

An internet search showed them for sale at the following distributor:
https://testeeurope.eu/fuse-630-ma-1000-v-c48976
https://testeeurope.eu/fuse-11-a-1000-v-c48975

[EEVblog]

FYI, there is another fuse related video: