Fuses for Brymen 867/9 - Page 1
Forum section: electronics / testgear

author: Mr Simpleton
author_rank: Unknown
timestamp: September 24, 2015, 08:32:35 pm
content: So I did a dumb thing... now the 1A fuse in my Brymen DMM is toast. Should be a simple thing to replace, but things are abit odd! The fuse is rated 1A / 1kV but most "low current" fuses for DMM's are raded 440mA. Reading up on the topic I notice that some docs do mention 440 mA in the 869!Question is, will a 440 mA fuse sufficient? As Fluke do use 440mA/11A the 440mA is way more common

author: soren
author_rank: Regular Contributor
timestamp: September 24, 2015, 08:47:28 pm
content: If you are willing to derate your meter a bit, Reichelt has the big 10x38mm fuses in cheap 500VAC variants in addition to the expensive 1000VDC ones. These also come in a wider range of values:http://www.reichelt.de/index.html?ARTICLE=54034(0.5A fast)http://www.reichelt.de/index.html?ARTICLE=54035(1A fast)http://www.reichelt.de/index.html?ARTICLE=54040(10A fast)

author: mimmus78
author_rank: Unknown
timestamp: September 24, 2015, 09:55:47 pm
content: You can search for "BUSS FUSE DMM-B-44/100-R" this should be original part number ... as Brymen reseller I have some of this fuse here just in case, so if you do not find locally just drop me a pm and we will see how to arrange shipment of the small part.Just curious: on manual the lower range current is rated as 0,44A and on the multimeter cover is 0,6A ... where did you get 1A?

author: markce
author_rank: Regular Contributor
timestamp: September 24, 2015, 10:09:47 pm
content: Safety fuse for the DMM is a (very) fast one, right? Please select the correct one if you order a cheaper replacement.

author: Mr Simpleton
author_rank: Unknown
timestamp: September 24, 2015, 10:29:33 pm
content: Plot thickens... I just re-opened my 867... it comes with Littlefuse KLK-1 and KLK-10 both rated 600 V MAX!And on the front cover "Max 1000V"So I assume the meter is not meeting the CAT safety standard, and why Brymen tries to cut corners like this?This sucks!!!I'll grab a pair of Buss fuses at work, we do have them for our Fluke 87's...Meter had never been opened before today, and the "safety" sticker from TME was still intact.

author: Mr Simpleton
author_rank: Unknown
timestamp: September 24, 2015, 10:35:56 pm
content: Quote from: mimmus78 on September 24, 2015, 09:55:47 pmWould be interesting to how the meter uses the lower range protection, it do have up to 499 mA reading, and putting in a fast acting 440 mA fuse seems to be asking for troubble. I guess this is the reason for 1 A but the low voltage specs smells bad

author: Deckert
author_rank: Regular Contributor
timestamp: September 24, 2015, 11:02:48 pm
content: Quote from: Mr Simpleton on September 24, 2015, 10:29:33 pmBrymen are not cutting corners:The Brymen 867 specifications clearly state: 1000V between COM and V terminals (AC & DC) and 600V AC between COM and A/mA terminals.The Brymen 869 specifications state: 1000V between COM and all other terminals (AC & DC).http://www.brymen.com.tw/product-html/cata860/BM860_Catalog.pdf--deckert

author: PedroDaGr8
author_rank: Super Contributor
timestamp: September 24, 2015, 11:37:32 pm
content: They also say it on the board itself, I have a BM869 review waiting for a repaired laptop. Brymen is very clear about this voltage limitation and don't try to hide it at all.Sent from my LG-ls990 using Tapatalk

author: Mr Simpleton
author_rank: Unknown
timestamp: September 25, 2015, 06:36:07 am
content: OK, still a bit confused how they use 0.44 mA fuse and have measure range of 500 mAThis is what Brymen support told me:Your model is BM867, not BM867s. BM867s the upgraded model of BM867. They use different fuses. Details are:BM8671A/600V fuse10A/600V fuseBM867s0.44A/1000V fuse11A/1000V fuse

author: Deckert
author_rank: Regular Contributor
timestamp: September 25, 2015, 08:57:22 pm
content: Quote from: Mr Simpleton on September 25, 2015, 06:36:07 amSeems pretty clear. You have the 867 (not 867s), so use the 1A/600V fuse.I opened my 867, it had the 1A/600V KTK-1 fuse in it. This one:http://uk.rs-online.com/web/p/cartridge-fuses/4588504I ordered a pack of five, so I'm all set for the future for any stupid mistakes I might make in terms of measuring current. They clearly went for a closer-tolerance fuse in the 867s, but on the other hand, my 867 is a little more tolerant to any mistakes I might make.--deckert

author: Mr Simpleton
author_rank: Unknown
timestamp: September 25, 2015, 09:36:03 pm
content: Agree the KTK-1 is the way to go... but how do they get away with the 440 mA fuse in 867/9s? Seems once you reach "almost" full scale of 500 mA you will burn the fuse??

author: Deckert
author_rank: Regular Contributor
timestamp: September 25, 2015, 10:55:35 pm
content: Quote from: Mr Simpleton on September 25, 2015, 09:36:03 pmThis is actually a good question. I went and had a look at the 440mA fuse datasheet (I couldn't find the Bussman datasheet for it, but used another 440mA cartridge fuse datasheet). The interesting thing is that the blow-time of this fuse is measured in several seconds. At 500mA, it takes 90s to blow. At 440mA it takes just over 1000s seconds to blow.So I suspect they might be taking advantage of the "quick" blow characteristic to make sure the 500mA limit is not exceeded?I have not seen the 867s specs - maybe they changed the specs to be slightly lower in exchange for better safety rating?--deckert

author: Lightages
author_rank: Unknown
timestamp: September 26, 2015, 04:40:19 am
content: All of the new Brymens, example BM829S, have been redesigned to meet the latest IEC requirements. They all have fuses to match the highest voltage rating, and some have new input protection designs. Would I trust any of the earlier models to be safe? Yes. Are the newer revisions safer? Who knows? They are made to meet a specification. How many manufacturers have CATIV/1000V rated meters? Not many.

author: retiredcaps
author_rank: Super Contributor
timestamp: September 26, 2015, 04:48:00 am
content: Quote from: Deckert on September 25, 2015, 10:55:35 pmBussmann datasheethttp://www.farnell.com/datasheets/287359.pdfGeneral Information:• Designed for multi-meters only.• Intended to carry 100% of rated current indefinitelyAlso seehttp://www.eevblog.com/2012/10/26/eevblog-376-multimeter-fuse-diode-followup/