Difference between Bussmann fuses: DMM-B-44-100 x DMM-44-100 ? - Page 1
Forum section: electronics / testgear

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: November 18, 2015, 11:22:09 pm
content: I somehow blew the 440mA fuse on my Fluke 17B+ (honestly, I didn't put more than 100mA through it).According to the manual, the Fluke replacement part. no. for it is 943121, which is a Bussmann DMM-44-100.The problem is that the only similar Bussmann fuse I've been able to find around here, for a reasonable price (around US$ 7), is the Bussmann DMM-B-44-100. According toits datasheet, it has the same dimensions and most of the specs of the one removed from the Fluke.What bothers me is the "B" in the model name. Is it really the same fuse and thus can be bought as a replacement, or is it a totally different thing? In other words, can I buy the Bussmann DMM-B-44-100 to replace a DMM-44-100 ?Thanks in advance.

author: helius
author_rank: Super Contributor
timestamp: November 18, 2015, 11:35:44 pm
content: I think I ran into this issue several years back when shopping for fuses. Some cylindrical fuses have a "bump" on the end, and are otherwise the same. The 'B' part may be like that if you look at the dimensional drawing, or they may not show it. I don't know for sure why, it could be a kind of key for situations where inserting the fuse in the wrong slot could be dangerous. If space is not too constrained, the "bump" fuses will fit in normal side clips exactly the same way as regular fuses.

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: November 18, 2015, 11:47:30 pm
content: Thank you.I looked for images of them to see where the bump is. Visually they look the same to me. The datasheet of the "B" model also states is has the same dimensions of the original Fluke 943121.Edit: this page on Amazon:http://www.amazon.com/Fluke-440-0-4A-1000V-Fuse/dp/B007Z2RL12state that the 2 fuses are the same. I wonder if I should trust them.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: November 18, 2015, 11:51:00 pm
content: Watch out, there's apparently some fakes floating about:https://www.eevblog.com/forum/beginners/beware-when-buying-dmms-on-ebay-fuses-ain't-cheap!/30/

author: helius
author_rank: Super Contributor
timestamp: November 18, 2015, 11:54:40 pm
content: I think the fuses with a bump had an "-R" suffix, not B. So I'm not completely sure what that is.

author: ModemHead
author_rank: Frequent Contributor
timestamp: November 19, 2015, 12:03:28 am
content: I do not know why, but at some point in time Bussmann changed the designation from "DMM" to "DMM-B". Every time I've ever researched them, the "B" version is listed as the replacement for the original. Never have seen any "bumps" on them.Other equivalents to DMM-B-44/100 and DMM-B-11A you may find:Littlefuse FLU.440 and FLU011Ferraz Shawmut FSM44/100 and FSM11

author: joeqsmith
author_rank: Super Contributor
timestamp: November 19, 2015, 12:16:22 am
content: If you were looking for a deal, Fluke sells these with 5 pcs. in a package. PN# 203414.http://www.amazon.com/Fluke-203414-Digital-Multimeter-Replacement/dp/B009386DZ6

author: Macbeth
author_rank: Super Contributor
timestamp: November 19, 2015, 01:22:21 am
content: You should do what I do - take those pricey fuses out and keep them somewhere safe. The last thing you want is to blow them and fork out the cost of a meter just to replace them. I use a bit of wire, rusty nail, or a milk bottle top as a suitable replacement.

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: November 19, 2015, 03:06:31 am
content: Thank you for all the replies.Quote from: joeqsmith on November 19, 2015, 12:16:22 amI would love to, but they won't ship to Brazil. Actually, none of the Amazon merchants ship these fuses to Brazil. I can buy them on e-Bay though, but there are no guarantees it won't be fake fuses.Quote from: Macbeth on November 19, 2015, 01:22:21 amI am not being cheap on the fuses - I know they cost a pretty money. What I don't like is being ripped off by most Brazilian e-tailers, that charge up to US$ 35 a piece (like Farnell Newark Brazil) just because there are only a handful of places that sell these fuses around here. I found one that has them for the equivalent to US$ 7, but like I wrote, they have a slightly different model (with the "B", and hence my doubt if they are the same model).Now that I think of it, and after reading Paul Moir's link, I am beginning to suspect the deal I found is too good to be true (US$ 7/pc). They are selling the fuse here for the same price some merchants sell them on Amazon.com. I am suspecting these might be fake.Quote from: ModemHead on November 19, 2015, 12:03:28 amThank you. I think this is the answer I was looking for. Apparently, however, Bussmann continues to manufacture both models in their Mexico plant, according to a document I found:http://www.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/product-notices/bus-ele-pcn-mfg-change-midget-fuses-10-10-12-bu.pdf(look for items 120 and 121)

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: November 23, 2015, 08:50:13 pm
content: I got the replacement fuses (3x) today. Here's a picture of them (in blue), along with the original that came in the Fluke 17B+ (purple):They don't look like counterfeit ones, and I spoke to the owner of the e-store before buying, stating my concern about fake units that have been flooding the market. The assured me that he sources these fuses directly from Bussmann, without going through Fluke, and that's how he's able to sell for a price that's half of what other sellers in Brazil are asking.My brief research about counterfeit Buss fuses indicate that most counterfeit/fake fuses:- have a different tool mark where the metal cap is crimped to the body.- look the sticker was printed on an inkjet printer- don't have an "A" stamped on the end of one of the caps (all 4 of mine do)In terms of sizes, these fuses are 0.05mm wider (10.30 x 10.35mm) , and 0.45mm longer than the original (34.55 X 35.00mm). Size is consistent in all 3 of them.Edit 1: Resistance in each of them is consistent and measured at 1.2 Ohms by the Fluke 17B+.Edit 2: and finally, it fits perfectly in the Fluke 17B+, and even if it were about 5mm longer, it would still fit.What do you guys think?

author: rsjsouza
author_rank: Super Contributor
timestamp: November 23, 2015, 09:25:08 pm
content: 1.2 ohms seems high to me, but I may be wrong. I can measure a few later today.

author: Macbeth
author_rank: Super Contributor
timestamp: November 24, 2015, 12:38:28 am
content: No idea - all I see is a huge space in your post with a greyed out "No Entry" road sign.

author: rsjsouza
author_rank: Super Contributor
timestamp: November 24, 2015, 03:41:50 am
content: Well, I measured mine and they are all around 0.8ohms. However, compounding the resistance of the leads brought the total to around 1 ohm. So, 1.2 ohms seems reasonable. (the 11A fuse one was 0.1 ohm)The fuses I have are the non-B version and are 34.65mm height x 10.2mm diameter on the metal cap (11A fuse was 38.2mm X 10.2mm). Average weight was 6.4g (8.3g the 11A fuse).

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: November 24, 2015, 01:55:25 pm
content: Quote from: Macbeth on November 24, 2015, 12:38:28 amFunny. The pic is hosted on Google Photos. Have you tried clicking on it? Anyway, here'sanother link to it.Quote from: rsjsouza on November 24, 2015, 03:41:50 amThank you.I tested 2 of mine again (the ones I am keeping as a backup), with a Fluke 117 and this time I got 0.8 Ohms on both of them.Intrigued by the results, I tried measuring with the 17B+ again. This time it measured 1R1, but after several seconds, it decreased to and stabilized at 0R8. Can you explain this?

author: Tom45
author_rank: Frequent Contributor
timestamp: November 24, 2015, 02:44:49 pm
content: Quote from: AlxDroidDev on November 24, 2015, 01:55:25 pmWhen I click on that link it wants me to log in to my (non-existent) Google account. I didn't see an image in your previous post either. It must only be valid for people that have a Google account.

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: November 24, 2015, 03:01:35 pm
content: Quote from: Tom45 on November 24, 2015, 02:44:49 pmSorry about that. I copied the photo to another site, and now you should have no problem with it:http://www.alexsimonetti.com.br/uploads/BussDMM-B-44-100.jpg(warning: 1.7 Mb)

author: rsjsouza
author_rank: Super Contributor
timestamp: November 24, 2015, 06:39:45 pm
content: Quote from: AlxDroidDev on November 24, 2015, 01:55:25 pmThe only way I can explain this is a simple bad contact - the varying resistance was probably influenced by a thin coat of grease or rust on the leads that may have been "carbonized" or destroyed by the temperature increase caused by the current flowing through the point of contact - all this in an infinitesimal scale, of course. Measuring low-level resistances with handheld multimeters sometimes can be tricky.

author: ioclk
author_rank: Newbie
timestamp: January 09, 2017, 09:36:46 am
content: Hi,I know it's an old thread but I was looking for that B meaning of the Bussman Fuses.The only document I found iswww.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/BUS_Ele_ARRA.xlsand results that the differences are ARRA and NAFTA qualifications.Bussmann P/NARRA Qualifies?Nafta Qualifies?DMM-11A-yesDMM-11A-10-yesDMM-B-11AyesyesDMM-B-44-100yes-Hope it may help someone.

author: MacMeter
author_rank: Frequent Contributor
timestamp: February 03, 2017, 02:21:28 pm
content: Quote from: ioclk on January 09, 2017, 09:36:46 amAs I was gifted a couple of Bussmann DMM-11A fuses from a friend who sold his Fluke 87v, I also wondered if they would be ok to use in my new EVVBlog BM-235 meter. The meter specs call for a Bussmann DMM-B-11A, the only difference being the "B", in the fuse code. So I just called Bussmann/Eaton, and was told they still make both models, the "B" designation is for the ones they sell to Fluke, the non "B" fuses are for general market, but was told they are EXACTLY the SAME.

author: SrMofo
author_rank: Newbie
timestamp: February 22, 2017, 05:28:37 pm
content: Quote from: MacMeter on February 03, 2017, 02:21:28 pmThink you may gotten the information backwards.I have a 'genuine' fuse. Part number DMM-11AR, purchased from Grainger. You can see on the cap it is imprinted "BUSS DMM 11A"I also have 4 Fuses purchased from Amazon. Part number DMM-B-11A. There is nothing imprinted on the caphttps://www.amazon.com/gp/product/B007IV5KPE/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1Now what does the R stand for?1 thing I do notice is that all 4 Amazon fuses DMM-B_11A have very small dimples stamped into the cap. They look too smal to be of any practical value for retention so I really have no idea

author: MacMeter
author_rank: Frequent Contributor
timestamp: February 22, 2017, 06:38:31 pm
content: Quote from: SrMofo on February 22, 2017, 05:28:37 pmWith all the online searching and phone calls I made trying to track them down, it's certainly possible I got it backwards or the rep did. But the bottom line is, according to Bussmann, they are the SAME speced fuses. Now as far as how they may be represented on various websites, that's a crap shoot. For example, I find many product photos on Amazon, are NOT the actual product being sold.

author: Elemecca
author_rank: Newbie
timestamp: July 02, 2018, 08:07:11 am
content: It's not obvious because a lot of the distributors are terrible at labeling multi-packs, but the product that typically costs US$35 from the reputable distributors (DigiKey,Mouser,Newark) is a carton of 10, which is how they ship from the factory according to the datasheet. That makes the price US$3.50/ea, which is about the best price on these you can get. Mouser gets some rare kudos for having "Factory Pack Quantity: 10" in their spec list; DigiKey and Newark don't show it at all but I think we can assume that their pricing isn't 10x Mouser's.(resurrecting this old thread because it's one of the top Google hits for "Buss DMM-44/100")

author: H.O
author_rank: Frequent Contributor
timestamp: July 02, 2018, 10:38:54 am
content: Are you 100% sure about that?Mouser for example, yes it does say that theFactory Pack Quantityis indeed 10 but in the description it saysSold Each.Then again, $35 just seems unreasonable for a single fuse but if the price is for a pack of 10 Mousers price is less than half compared to European distributor Distrelec who charges around $7 each at quantity 10.Very strange....

author: wraper
author_rank: Unknown
timestamp: July 02, 2018, 10:59:08 am
content: Quote from: Elemecca on July 02, 2018, 08:07:11 amFactory pack is factory pack, not what they'll sell you by buying one item. Here is exampleMouser. Do you really think they'll sell you 120 MCUs for $ 0.83?

author: trobbins
author_rank: Frequent Contributor
timestamp: July 02, 2018, 11:06:23 am
content: On the topic of the two different fuse designators, I'd suggest that Fluke gained compliance to various standards with a specific parts list, and so have to state the specific replacement fuse model that will allow that compliance to be maintained.

author: SG-1
author_rank: Regular Contributor
timestamp: July 02, 2018, 12:46:43 pm
content: The R probably stands for Rejection. Between Rectifier & Safety T Plus in the link below.https://www.fusesunlimited.com/glossary.aspx

author: SG-1
author_rank: Regular Contributor
timestamp: July 02, 2018, 07:19:53 pm
content: Here is a KTK & KTK-R fuse assembly.

author: SG-1
author_rank: Regular Contributor
timestamp: July 02, 2018, 07:52:11 pm
content: More about rejection fuses:http://www.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/solution-center/technical_library/BUS_Ele_Tech_Lib_Class_R_Fuses.pdf

author: MFairleigh
author_rank: Newbie
timestamp: December 19, 2018, 08:55:19 am
content: Just replying here in case anyone else finds this thread as I did, searching for clarification on these DMM fuses. I received the following response directly from Fluke yesterday:“The DMM-11A is an older version of the DMM-B-11A. The DMM-11A-R and DMM-R 0.44 refer to a RoHS compliant part.“According to the UL Cert from Cooper Bussmann the DMM-11A, DMM-B-11A and DMM-11A-R fall under the same UL cert. Likewise for the DMM, DMM-B, DMM-R 0.44 fuse.“It looks like over the years they have changed the model number in the catalog and updated the cert with the new model, but kept the same ratings and UL certification.”So, in case anyone besides me is still uneasy about using the “B model” versions of these fuses, the horse’s mouth says they should be fine.Sorry for bumping such an old topic.Mike