Fake Fluke Fuses? (630mA) - Page 1
Forum section: electronics / testgear

author: Supply Man
author_rank: Newbie
timestamp: May 09, 2018, 12:32:30 am
content: About a month ago I bought a lot of Fluke 37s for cheap on ebay. Upon testing them, I discovered that all of them had blown 630mA fuses, so naturally I went and ordered replacements. After receiving them, I noticed that they are completely lacking the markings on the fuse that I had expected from both the old fuses and the pictures I have seen. Further reading about the large amount of cheap/fake fuses on the market in conjunction with the different looking fuses and their low price leads me to think that they are fakes.I have a few questions. First, where would you guys recommend I buy replacement fuses for my multimeters in the future to avoid this issue? Second, are these at all safe? Will I be seriously risking my equipment/myself if I use them?Here is the amazon listing I bought them from:https://www.amazon.com/gp/product/B0002SRIM8I have also included pictures of the original bussman fuses, the new ones I received, and the packaging they came in below.The original fuses are on the left.EDIT: Sorry about the massive images, will upload smaller ones next time.EDIT 2: For some reason I didn't check digikey.A 5 pack for $10 + shipping doesn't seem so bad:https://www.digikey.com/short/jmc105

author: retiredcaps
author_rank: Super Contributor
timestamp: May 09, 2018, 02:17:27 am
content: Quote from: Supply Man on May 09, 2018, 12:32:30 amUnless it is sold by Fluke or Amazon, 3rd party sellers on Amazon are hit and miss. If they are much cheaper than reputable places like Digikey or Mouser, they are likely fake.The fact that they have no markings should be considered fake. Get your money back from Amazon's legendary service.QuoteWith Digikey, you are likely to get the real thing.

author: Supply Man
author_rank: Newbie
timestamp: May 09, 2018, 02:35:27 am
content: Thanks for confirming my suspicions. I'm new to this stuff so I figured I'd ask and make sure rather than guess! Will be returning the fuses and buying from digikey. Thanks again!

author: EEVblog
author_rank: Unknown
timestamp: May 09, 2018, 03:24:42 am
content: Quote from: Supply Man on May 09, 2018, 12:32:30 amYep, well known problem. Majority of the expensive HRC fuses on ebay would be fake.

author: Electro Detective
author_rank: Super Contributor
timestamp: May 09, 2018, 05:25:17 am
content: 630ma 250 volt fuses would be difficult to stuff up, be they originals or knockoffsIf I can't source reputable replacements, I test a couple of knockoffs in a packet on a test jiggy,and if rated at 630ma they blow anywhere from 550 to 800ma at 240 volts, with a good fast zap after holding continuous current,...and glass, metal, and sand don't fly everywherethen the rest in the packet should do the jobWith the higher voltage HRC fuses it's not that easy to test, best is to bite the bullet and get the correct ones

author: Fungus
author_rank: Super Contributor
timestamp: May 09, 2018, 09:54:35 am
content: My Fluke 37 has two fuses in series on the mA input jack, a small 630mA fuse in series with a much bigger 2A HRC fuse.The 630mA fuse is only there to save the expensive 2A fuse from user stupidity. I don't think it matters much if the small fuse is 'genuine' or not, it's the 2A fuse that will save you if you go poking around a substation with one of these.OTOH it matters that it's 630mA, not some other value and if you've been ripped off you should ask for a refund.

author: wraper
author_rank: Unknown
timestamp: May 09, 2018, 10:08:48 am
content: Quote from: retiredcaps on May 09, 2018, 02:17:27 amThey have marking on the caps. They certainly are not Bussmann but I don't know if fluke may use several sources of such fuses. If the seller was amazon itself, I don't think there is high chance of them being fake.

author: Electro Detective
author_rank: Super Contributor
timestamp: May 09, 2018, 10:37:46 am
content: It looks like legit Fluke packaging to meCheck for Amazon comments on that product,email Fluke support and hope it doesn't get deleted as s p a m (as they do sometimes LOL)Any chance to get those engraved/stamped markings on the suspected fakes enlarged and readable?OTOH perhaps it's a real deal no frills fuseFluke gets them cheaper but still stitches you full retail

author: Supply Man
author_rank: Newbie
timestamp: May 10, 2018, 05:52:14 am
content: Quote from: Fungus on May 09, 2018, 09:54:35 amGood to know. I was wondering why there were 3 fuses. Is this common practice?

author: Electro Detective
author_rank: Super Contributor
timestamp: May 10, 2018, 06:04:12 am
content: On many vintage Fluke meters yes AFAIKOne internal large HRC fuse ($$ !),one lower rated user replaceable glass or ceramic fuse,and one user spare

author: Fungus
author_rank: Super Contributor
timestamp: May 10, 2018, 06:18:35 am
content: Quote from: Supply Man on May 10, 2018, 05:52:14 amNot any more.(and I'd like to know why not, it's a really good idea IMHO)

author: Whales
author_rank: Super Contributor
timestamp: May 10, 2018, 06:40:11 am
content: Have you tried cracking one open to see if it has quenching sand inside? Worth it just for a bit of fun,my fake fuses from ebay didn't

author: Supply Man
author_rank: Newbie
timestamp: May 10, 2018, 08:16:01 am
content: Quote from: Whales on May 10, 2018, 06:40:11 amI am gonna return them for refund. Probably shouldn't break one.

author: wraper
author_rank: Unknown
timestamp: May 10, 2018, 08:28:42 am
content: Quote from: Supply Man on May 10, 2018, 08:16:01 amYou still did not say if it was from amazon itself. As if you did not choose another seller, it is. Also you did not post any photo of the fuse markings on caps. With current information, it seem to be concern about nothing. What you buy are 630mA fuses, not bussmann fuses. It's up to Fluke to choose what supplier they use.

author: wraper
author_rank: Unknown
timestamp: May 10, 2018, 08:37:56 am
content: BTW, probably they are Bussman. I see ..USS on one of the caps. Then check how they look on the datasheethttp://www.farnell.com/datasheets/19206.pdf?_ga=2.115188551.1542365325.1525681226-1354045019.1503601835(marking on the caps).If you want marking on ceramic, those are GDA serieshttp://www.cooperindustries.com/content/dam/public/bussmann/Electronics/Resources/product-datasheets/Bus_Elx_DS_2014_GDA_Series.pdfAs of specs, they are exactly the same thing.