Multimeters that do not appear to meet their safety specs. - Page 1
Forum section: electronics / testgear

author: Lightages
author_rank: Unknown
timestamp: October 27, 2012, 01:48:39 am
content: Revised: September 27 2013 18h10 UTIt is my intention here to start listing multimeters that appear to have designs or implementations that do match the intent of their rated CAT levels.The intent of this thread is to provide at least a partial list of multimeters that are to be assessed on their physical and feature merits rather than to rely on their stated CAT ratings for assumption of safety. I will update this post each time I see a new post with a new multimeter so as to keep the list in one spot. I hope to save someone grief or injury by compiling this information.A list of mulitmeters that appear to be properly designed and can be recommended is here:https://www.eevblog.com/forum/product-reviews-photos-and-discussion/a-list-of-recommended-multimeters/Please post the manufacturer, model, CAT ratings, fuse type and voltage, any images that support a suspected failing in meeting the specifications of the CAT rating, or ANY other information that causes suspicion that the CAT rating is not being met.The criteria, in part, for these variations from meeting the ratings can be gleaned from here:https://www.eevblog.com/forum/projects-designs-and-technical-stuff/cat-ratings-and-interpretation/The main criteria is that all inputs must be able to withstand the maximum CAT ratings in all modes of operation, connected incorrectly or not, without harming the user. Current measurement protection must meet the CAT voltage rating as well, in other words fuses used must be rated for the maximum CAT rating on the meter.If you have a meter that claims it is UL listed, you can search to see if it actually by searching for its certification here:http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/index.html(thanks to grenet for the link). Each UL listed item will have a UL sticker on the piece of equipment. If you do not find this sticker then you probably have a fake UL listing on the equipment and it is not to be trusted until the listing can be verified using the link previously mentioned. A UL rating is no guarantee that the manufacturer continues to make the meter with any level of quality or the same way. Different countries also have their own standards. If a meter has a UL listing it does not guarantee that the meter actually meets its current CAT ratings claim according to the most recent CAT rating rules. For example the Extech EX330 is UL listed but does not meet the most recent rules for its claimed CAT rating.Fluke do not recommended using the CE mark as a guide:http://support.fluke.com/educators/Download/Asset/2096653_6003_ENG_D_W.PDFThey suggest UL, CSA, or TUV independent test markings.(as per Dave's post)Yes, I asked Dave if this was a good idea and he said he had no objections to this.It seems to me that listing meters with flaws is easier than proving compliance. Anyone can demonstrate a problem, almost no one here can prove compliance.This list can never be comprehensive because there are so many junk meters on the market that it is impossible to list them all. Please use the information here to assist in assessing a meter for use on any high energy circuit even if you do not open the meter and provide a new submission. Generally one should never rely on the markings on a meter to truly reflect its safety.Some people have been modifying fuse holders and adding over voltage protection components to their meters in an attempt to improve the safety of the meter. Adding better fuses is probably never a bad idea but adding over voltage protection components might not be a good idea. It ispossiblethat the over voltage devices were omitted to achieve safety and not to avoid cost. Perhaps an MOV exploded during testing but when the meter was tested without the MOV the meter passed the test.Just because a meter is not listed here does not imply it is safe or that it meets its CAT rating, it just means it is not listed. Many brands are just "rebranding" of other meters. Uni-Trend meters are also sold as Tenma, Voltcraft, and other brands for exampleThe list:Uni-Trend UT71E (all A,B,C,D,E)CatIII/1000V CATIV/600V glass fuses used on current ranges with rating of 250V,battery lead with 600V insulated wires touching unprotected circuit board trace for Volts/Ohms input, might be an issue, might not.No indication on face of meter of low voltage fuses. (submitted by lightages)Uni-Trend UT61E (all A,B,C,D,E)CATIII/1000V CATIV/600V ceramic fuses rated at 250V used on current ranges with 250V voltage warning on meter.Be aware that the UT61E has a different version available in Europe. It did not pass the labelled CATIV/600V CATIII/1000V ratings. The revised version is now rated at CATII/600V and CATIII/300V and has upgraded fuses and more input protection. The safety of this meter is a complete unknown now(submitted by lightages)Victor VC9806+CATIII/1000V glass fuses used on current ranges with rating of 250V, battery within clearance allowance for 1000V from fuses, no indication on current inputs of voltage limitations. (submitted by lightages)Uni-Trend UT33CCATI/600V CATII/300V 10A range unfused, MA range glass fused with rating of 250V with warning of maximum 500V to be applied on the common volt/ohm/ma current inputs. (submitted by lightages)Vichy VC99CATII/1000V Current ranges use glass fuses rated at 250v with no warning of lower voltage, insufficient creepage distance from fuses to other parts, battery wire with unrated insulation passing through circuit board in contact with high current range circuit trace before fuse. (Submitted by T4P and review by electronupdate)Minipa ET-997CATII/1000V 20A range has glass fuse rated for 250V with no warning of lower voltage. (Submitted by T4P, teardown by metalphreak)Mastech MS8218CATIII/1000V Current ranges have ceramic fuses rated for 500V with no warning of lower voltage (Submitted by T4P, review by mjlorton)Extech EX330CATIII/600V CATII/1000V Current ranges have glass fuses rated for 250V with no warning of lower voltage (Submitted by T4P, reviewed by Dave Jones)Additional information and reviews on different Extechs show that Extech EX series are to be avoided in general. The quality control appears to be so bad that parts are coming loose inside some meters from the factory, amongst other problems.Elenco M-2625alsoJaycar Digitech QM1535CATII/600V? MA current range has glass fuse rated for 250V with no warning of lower voltage. (Submitted by T4P, reviewed by Dave Jones)Global Specialties Pro-50CAT?, stated 1000VDC/700VAC MAX, 10A range not fused, MA range has glass fuse rated for 250V with no warning of lower voltage. Technically this meter appears to not be CAT rated so no implied safety rating(Submitted by T4P, reviewed by Dave Jones)UNI-T UT90ACATII/1000V CATIII/600V ceramic fuses rated at 250V used on current ranges with 250V voltage warning on meter. 3 PTCs for input protection (Submitted by T4P)UNI-T UT90CCATII/1000V CATIII/600V GLASS fuses rated at 250V used on current ranges with 250V voltage warning on meter. Some diodes to protect mA range? and 3 PTCs for input protection (Submitted by T4P)Ideal 61-342CATIII/600V Ceramic fuse used on MA range rated for 500V with no warning of lower voltage fuse. Technically this is a non-compliance to standards but a minor and probably inconsequential one. (Submitted by Lightages, reviewed by Dave Jones)BK Precision 2709B/2712CATIII/600V CATII/1000V Ceramic fuses used on both current ranges rated at 500V with no warning on meter. (Submitted by Lightages, reviewed by Dave Jones and 2712 by carloscuev)Any Meter with the model number "830"All of these low priced meters are junk just waiting to blow up in your hand. (Submitted by Lightages)Uni-Trend UT120CCATII/600V Self recovery 250V 400mA fuse over current protector on milliamps range. Reviewed by Wytnucls herehttps://www.eevblog.com/forum/reviews/uni-t-ut120c-review-and-tear-down/(Submitted by Lightages)Brymen BM867CATIV/1000V Fuses rated only for 600V which is strange because the bigger brother BM869 which is built the same way has 1000V fuses. It appears that this problem can be corrected merely by installing the higher rated fuses. Reviews by mjlorton on his websitewww.mjlorton.comand here by iloveelectronicshttps://www.eevblog.com/forum/reviews/brymen-bm-867-teardown-pictures/(Submitted by Lightages)Amprobe AM-140-ACATIV/600V CATIII/1000V for voltage and lower rated for current. Fuses rated only for 600V which is strange because the bigger brother AM-160-A which is built the same way has 1000V fuses. It does state in the specs that the current range has a lower rating but it is not permitted to do so in the current CAT ratings standards. It appears that this problem can be corrected merely by installing the higher rated fuses. Review by jwrtigerhttps://www.eevblog.com/forum/reviews/amprobe-am-140-a/msg155623/#msg155623(Submitted by Lightages)UEi DM5BNo CAT rating but claimed 500V safety while using fuses of 250V. (Submitted by Wytnucls)Mastercraft sold by Canadian TireA company named Canadian Tire in Canada rebrands and sells many different multimeters over the years and almost all of them do not come close to meeting any safety standard. (Submitted by 2dfx)Amrpobe AM-220/240CATIII/600V with fuses rated only for 250V with warning of lower rating on meter. This made worse by the fact that the order of the input jacks have been changed which could lead to errors in use, and that the MA range shares a common jack with the V/ohms range.(Submitted by ivan747)Digitek DT-2843RCATIII/600V with fuses rated only for 250V with warning of lower rating on meter. Reviewed by Lightages here:https://www.eevblog.com/forum/testgear/review-digitek-dt-2843r-trms-for-less/(Submitted by Lightages)Digitek DT-4000ZC / TekPower TP4000ZCCATIII/600V with fuses rated only for 250V with warning of lower rating on meter. Reviewed by mjlorton.com (Submitted by Lightages)Elenco M-2666KRated 1000V (No CAT rating implied) with fuse rated only for 250V with no warning of lower rating on meter, 20A range unfused. (Submitted by rexxar)Mastech MS8229 / Protek 6300CATIII/600V CATII/1000V with fuses rated only for 500V with no warning of lower rating on meter. (Submitted by madsci)

author: Unknown
author_rank: Unknown
timestamp: October 27, 2012, 01:02:27 pm
content: Wouldn't it be more efficient to list all of the instruments that do conform to safety standards? Since the CE mark requires conformity to EN61010 for multimeters, I would expect essentially any cheap multimeter and probably many of the < $100 meters sold in the EU to be in violation unless explicitly limited to SELV. Just the lack of over voltage category markings would be a violation, not to mention the fact that they may not even conform to CAT I.

author: Astroplio
author_rank: Regular Contributor
timestamp: October 27, 2012, 02:01:44 pm
content: Not a bad idea for this thread, but shouldn't we also consider the quality/safety of their probes?And if yes, then how can we comment on that? It looks to me it is hard to tell, but I personally would never touch mains voltage with a cheap multimeter's leads, just battery powered circuits.Also it would be cool if people could advise for improvements of listed instruments here, i.e. a HRC fuse replacement could be all that is needed in some of these DMMs.ThanksGeorge

author: Unknown
author_rank: Unknown
timestamp: October 27, 2012, 02:10:43 pm
content: I don't think there is any way to tell what needs to be changed without torture tests. If they skimped on the fuses, they may as well skimped on other critical areas like clearance, quality of components and enclosure. Just replacing one critical component may not be enough. It's much easier to determine if something definitely does not meet spec (glass fuse, insufficient clearance) than it is to guarantee that something will pass the relevant tests.

author: Wytnucls
author_rank: Super Contributor
timestamp: October 27, 2012, 02:13:51 pm
content: Quote from: alm on October 27, 2012, 01:02:27 pmI agree that it would be more efficient to list the meters that qualify, as that club is far smaller, in my view.Also, remember that these regulations changed recently and we don't know what the specifications were previously.

author: T4P
author_rank: Super Contributor
timestamp: October 27, 2012, 03:37:45 pm
content: UNI-T, Victor, Mastech does it to cut costs, it's any china's company policy.Okay, here's moreMS8218 (The socket's was for a 6.3x32)VC97/99 (the one dave reviewed)Minipa ET-997 (Yes, search for it on eevblog)And basically all of Victor meters, UNI-T and Minipa

author: Lightages
author_rank: Unknown
timestamp: October 27, 2012, 06:00:14 pm
content: Quote from: alm on October 27, 2012, 01:02:27 pmSeeing as I cannot personally test, nor can most others, the compliance to the CAT ratings stated on the meter, it is much easier to list any meter that has glaring obvious failures to match the CAT rating criteria. Stating the meter does meet CAT ratings is a very big undertaking whilst listing obvious flaws is easy for anyone to do.Another thing is that claiming that a meter is safe here could open anyone who makes that claim to liability should someone get injured using that model of meter.

author: Lightages
author_rank: Unknown
timestamp: October 27, 2012, 06:04:47 pm
content: Quote from: Astroplio on October 27, 2012, 02:01:44 pmYes of course, any flaw can be listed and described as I have mentioned. Just add a line of description of the problem.Quote from: Astroplio on October 27, 2012, 02:01:44 pmI would be happy for people to add any information or tips they have for improving the safety of their meter. One must realize that adding things does not necessarily make a meter safer. That omitted part might have been omitted because IT became the hazard under testing and removing it from the meter made it safer. An example might be when a manufacturer omits a voltage limiting device like a MOV because the MOV exploded during the testing and ruptured the case.

author: Lightages
author_rank: Unknown
timestamp: October 27, 2012, 06:09:26 pm
content: Quote from: T4P on October 27, 2012, 03:37:45 pmThanks for the additions T4P, but I request that if you find a meter that has obvious flaws that you describe what is wrong with them as I have demonstrated in my first post. If everyone just adds a meter with no description of what is wrong it can take me a long time to find the meter online, look at all the reviews or tear downs, and try to guess what you saw as a flaw.Of course if anyone has links to reviews or tear downs or images of the offending meters the links would be welcome too.

author: Simon
author_rank: Unknown
timestamp: October 27, 2012, 06:30:58 pm
content: sounds like a good idea to me, and we know what happens when stuff is listed on the net as bad, companies start to think about fixing it.

author: EEVblog
author_rank: Unknown
timestamp: October 27, 2012, 09:07:35 pm
content: Quote from: alm on October 27, 2012, 01:02:27 pmFluke do not recommended using the CE mark as a guide:http://support.fluke.com/educators/Download/Asset/2096653_6003_ENG_D_W.PDFThey suggest UL, CSA, or TUV independent test markings.Dave.

author: Matje
author_rank: Regular Contributor
timestamp: October 27, 2012, 10:37:13 pm
content: Quote from: Lightages on October 27, 2012, 01:48:39 amHmm, could it be that these differ between locales? Because the one I got here in Germany doesn't mention 250V, only 300V and 600V. I didn't open it to check the fuses though, the manual does indeed say 250V. I won't connect it to any CATIII or IV installations either...Where on the DMM is the warning located, image?

author: Lightages
author_rank: Unknown
timestamp: October 27, 2012, 10:55:36 pm
content: In the thread of the UT61E review that is 27 pages long!https://www.eevblog.com/forum/product-reviews-photos-and-discussion/uni-t-ut61e-multimeter-teardown-photos/

author: Unknown
author_rank: Unknown
timestamp: October 28, 2012, 02:15:33 am
content: Quote from: EEVblog on October 27, 2012, 09:07:35 pmIf you would have read until the end of the sentence that you truncated in your quote, you would have noticed that I wasn't at all suggesting relying on the CE mark. But since declaring CE conformity for a DMM requires conformity to EN61010, any CE marked DMM should be EN61010 compliant, regardless of any further markings or claims.

author: Lightages
author_rank: Unknown
timestamp: October 28, 2012, 03:50:39 am
content: Quote from: alm on October 28, 2012, 02:15:33 amExcept CE markings do not require that a 3rd party do the compliance testing. Any company can put a CE mark on their equipment if they believe, rightly or wrongly, that the equipment conforms to the standard. Its is obvious that many don't even with the CE mark.

author: T4P
author_rank: Super Contributor
timestamp: October 28, 2012, 04:58:40 am
content: Quote from: Lightages on October 27, 2012, 06:09:26 pmHere's a few problems with the ET-997, mA fuse is actually a polyfuseMS8218 : Wrong fuse fitted, that's a BS1362 fuseVC99 : Glass fuses as such ...Extech EX330 : GLASS FUSES!The elenco one dave reviewed : GLASS FUSES!GS PRO-50 : Glass fusesI even wonder how EX330 won the $50 shootout ... if only UT61E had lower prices back then, that would be the clear winner

author: Lightages
author_rank: Unknown
timestamp: October 28, 2012, 05:58:44 am
content: T4PI appreciate the submissions, but you could save me a lot of time trying to find the exact details of each meter if you would include those details in your submissions. Look at the list and see how I am doing this. Thanks again

author: Simon
author_rank: Unknown
timestamp: October 28, 2012, 07:44:40 am
content: CE marking is a joke and a farce, there is the "C E" mark, the real one and there is the "CE" mark that means china export (well we know what they hope we think it will mean).

author: Unknown
author_rank: Unknown
timestamp: October 28, 2012, 01:29:09 pm
content: OK, one last try, since people appear to insist on inferring from my words that the CE mark is somehow proof of safety.We all know that none of those cheap multimeters have a snowball's chance in hell of meeting IEC/EN 61010 unless limited to 30 Vrms or so. If the distributor (note that CE markings by Chinese manufacturers are invalid anyway) adds a CE mark, then that means they declare it to be compliant with IEC/EN 61010. All these meters therefore belong on this list. Since they are usually sold under lots of different brand names, this would be a pretty long list.

author: Lightages
author_rank: Unknown
timestamp: October 28, 2012, 03:28:10 pm
content: I certainly did not think you were saying the CE mark was something to follow. Yes I know that this list could be infinitely long, but I am willing to put the work in to keep compiling the list. I am sure the more popular meters will get listed and it might help some newbies make a better purchasing decision and maybe could save someone some injury.

author: T4P
author_rank: Super Contributor
timestamp: October 28, 2012, 05:00:58 pm
content: Sorry about that, i'll head out and grab these following meters :VC8145UT33DUT136C (China market only)UT204AUT511 (the shipping weight is 3.85kgs for god's sake!)Should make for a nice cat rating database (UT511 will wait, ain't cheap)UNI-T UT90ACATII/1000V CATIII/600V ceramic fuses rated at 250V used on current ranges with 250V voltage warning on meter. 3 PTCs for input protectionUNI-T UT90CCATII/1000V CATIII/600V GLASS fuses rated at 250V used on current ranges with 250V voltage warning on meter. Some diodes (WAUUWWWW!) to protect mA range? and 3 PTCs for input protection

author: Neilm
author_rank: Super Contributor
timestamp: October 28, 2012, 05:16:10 pm
content: Quote from: Simon on October 28, 2012, 07:44:40 amThe CE mark for safety will remain a joke unless local regulatory bodies start enforcing it. There have not been many cases in the UK that I am aware of where non-compliant meters were removed from the market. When they are, the issue should be published in as many trade issues as possible to make the fact that they are taking action as public as possible.What is the state in other countries? I know that several non EU countries have complained about non compliant meters on sale.Neil

author: Ivanko1
author_rank: Contributor
timestamp: November 01, 2012, 02:49:21 pm
content: Quote from: Lightages on October 27, 2012, 01:48:39 amWell... my Uni-T 61E from China, has 1A and 10A ceramic fuses, type BS1362, without any voltage. So I think it's trully 1000V fuses, unless someone proves the opposite.

author: Lightages
author_rank: Unknown
timestamp: November 01, 2012, 03:28:13 pm
content: BS1362 fuses are rated at 250V, so it is obvious that are not meant to be used above that voltage.

author: Ivanko1
author_rank: Contributor
timestamp: November 01, 2012, 04:22:11 pm
content: Ok, so what to do now, if I need measure sbout 380-400V?

author: Wytnucls
author_rank: Super Contributor
timestamp: November 01, 2012, 04:51:45 pm
content: Quote from: Ivanko1 on November 01, 2012, 04:22:11 pmIf you do it properly, with the probes in COM and Volt/Ohm jacks, there is no problem measuring high voltages, if your meter is rated CAT III 1000V.

author: Unknown
author_rank: Unknown
timestamp: November 01, 2012, 06:25:02 pm
content: If your meter is actually suitable for CAT III 1000V. The lack of suitable fuses does not convince me the designers did their job and actually tested it under the prescribed conditions. Any monkey can put that CAT III stamp on there, that's what this thread is all about.

author: Lightages
author_rank: Unknown
timestamp: November 01, 2012, 06:47:55 pm
content: I agree with ALM. When you start getting up to 380V plus you are getting into another whole world of hurt if something goes wrong. I would STRONGLY suggest that you find a meter with the proper design for these voltages/energies.My personal recommendations:Anything Fluke with a CATIII or CATIV 600V plus ratingAnything Agilent with a CATIII or CATIV 600V plus ratingAmprobe AM140 or 160Anything Extech with a CATIII or CATIV 600V plus ratingscratch those with the recent recallUEi DM 391/393/397Brymen DM85X or DM86XThe above are not guaranteed by me nor am I saying you will be safe no matter how you use the meters I have recommended.Where safety glasses no matter what meter you are using with high energy circuits. Wear heavy leather (dry and clean) gloves too. Better yet, take a course on electrical safety procedures if you think a UNI-T UT61E is a safe meter for 380V plus....I have seen too many "electricians" with burn scars on their hands and faces.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 01, 2012, 07:23:39 pm
content: Technically speaking, if you cannot trust your meter CAT ratings, you shouldn't use it for 240V measurements either. High voltage transients are possible at that voltage level too. Stick to battery voltages on electronic circuits.Buying a meter that has been tested by an independent body is never a bad idea, if you can afford it. If you are going to play with high voltages on a regular basis, you can afford it, even if it means not eating for a week.Remember that accidents have also happened with the best equipment available. So use your common sense and be sure to understand all the limitations of your instrument.

author: T4P
author_rank: Super Contributor
timestamp: November 01, 2012, 08:10:58 pm
content: Quote from: Ivanko1 on November 01, 2012, 02:49:21 pmAre you kidding me?@LightagesOK. To use a UT61E for 380V MAINS!!! (V range ONLY. Please.) In normal situations ... mess it up and your hand goes.1000V may be what they mean by low energy ONLY. Definitely not the 8000V rating CAT III isFact is, the fuse is wrong but the sockets can be swapped out

author: Unknown
author_rank: Unknown
timestamp: November 01, 2012, 10:54:06 pm
content: Quote from: Wytnucls on November 01, 2012, 07:23:39 pmAgreed. Although most 400 V circuits will be at least CAT III, while many 240 V circuits are CAT II, so transients can be larger on the 400 V circuit.Quote from: Wytnucls on November 01, 2012, 07:23:39 pmI concur. Even a very reliable tool like a CAT IV 600 V rated Fluke DMM should not give you the sense of absolute safety. Accidents can always happen, especially if you're not careful or focused on the task.

author: Lightages
author_rank: Unknown
timestamp: November 01, 2012, 11:05:27 pm
content: Yes that was my thinking as well ALM. It is one thing to play inside the house with wall sockets and with lower energy fused circuits. It is another thing to start playing with power house and heavy motor drive type power that 380V implies.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 01, 2012, 11:14:33 pm
content: Actually, in most of Europe, tri-phase voltages in the order of 380V are quite common in the house. Ovens, heaters and dryers can be connected to a higher voltage than the rest of the household.

author: Lightages
author_rank: Unknown
timestamp: November 02, 2012, 01:21:15 am
content: Ah yes I forgot about the big appliances. I would avoid using many meters on those circuits. I think I might still use my UT61E for that, but I would prefer anything else in the list I mentioned earlier.

author: Salas
author_rank: Frequent Contributor
timestamp: November 02, 2012, 07:58:32 am
content: Everything we should know about fuses.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 02, 2012, 08:38:55 am
content: Let me try to dispel some misconceptions about high voltage measurement.Let's forget about high voltage transients for a moment, as these are unlikely in the home environment, if you can discount lightning strikes and such on the supply side. (These would be just as lethal whether you're measuring 115V or 380V, by the way)Let's also assume that the meter is used properly, with the probes in the Volts/Ohms and COM jacks and the range selector on Volts.Let me also remind you that all protection devices (PTCs, MOVs and GDTs) only come in action for voltages higher than 1000V.Because of the high impedance (usually 10M Ohms on the Volt range and 2.5G Ohms on the mV range), the amps flowing through the meter have a very low value (about100uA) and the high 1000V voltage is reduced straight away to10 mV(assuming an impedance of 100 Ohms for the upstream circuit), as the current flows immediately through a network of beefy step-down resistors before hitting the measuring circuit. So the traces can be very thin on the Volts range and they usually are.So, in that situation, all CAT-rated multimeters are essentially the same and the main safety concern should be for the operator not to come in contact with the high voltage being measured.That brings us to the probes, their insulation and meter connections. Make sure that those have the correct CAT ratings and inspect your probe and meter connections. If you don't trust your probes, do what I did and buy a nice set of Fluke TL175 probes ($20.00), for peace of mind.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 02, 2012, 01:58:17 pm
content: Now, in the case of the UT-71, as Lightages pointed out, there is a very small clearance between the Volts trace and the 9V battery wires on the PCB (0.6mm on mine). This is what could happen if a short ever develops:I modified mine, with a proper PCB connection, extra insulation and a heat guard and got rid of the routing through the PCB.If you decide to modify your Uni-T, make the heat guard a lot shorter, otherwise it will interfere with the battery compartment seating.Here is also the original set-up for reference:

author: Lightages
author_rank: Unknown
timestamp: November 02, 2012, 03:02:52 pm
content: Quote from: Wytnucls on November 02, 2012, 08:38:55 amQuote from: alm on November 01, 2012, 06:25:02 pmAs ALM said. Although I agree that the chances of harm are pretty slim, there is always the concern that if the designer/manufacturer of a meter cut corners in one place then they might have in many others too. In all reality the UT61E looks well designed and I guess on second thought I probably was over stating the danger with that meter. It probably is fine for almost anything anyone would use it for in a home. Its biggest problem would arise from someone forgetting to put the leads in thewrongright terminals and blowing up a fuse inside.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 02, 2012, 07:51:20 pm
content: I think you meant to write "the right terminals"Talking about right terminals, the 71 actually beeps madly at you if you have the probes in the amps jacks with the range switch out of the A or mA/uA positions. Has the 61 got that safety feature?Here is the 71B with modified battery connections and a SIBA HRC 10A 1000V 30kA fuse installed:

author: Soertier
author_rank: Contributor
timestamp: November 02, 2012, 08:05:31 pm
content: Quote from: Wytnucls on November 02, 2012, 07:51:20 pmIt does not have that feature.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 02, 2012, 10:51:11 pm
content: Here is a picture of what the UT-71 should have been and may become, if the new regulations are respected:1000V HRC fuses and safe battery connections.The 500mA fuse is in a tight space. It's not touching anything right now, but I'm not too happy with the clearances. I will eventually install it into a small enclosure to prevent spark-overs.The 500mA fuse is a very fast SIBA HRC 1000V 50kA (part number:7017240)Ideally a 1000V gas discharged tube should be fitted behind the PTC, as the PTC is very slow to react to high transients.A MOV would do the job too, but they tend to catch alight under stress.

author: Unknown
author_rank: Unknown
timestamp: November 03, 2012, 12:19:32 am
content: Quote from: alm on November 01, 2012, 10:54:06 pmCould not agree more, any instrument is only as good as the way it is used and cared for. Often I've seen Flukes and other top shelf instruments belted about in a canvas tool bag and covered in oil and solvents. No device could be expected to retain absolute integrity in these situations.Similarly in high demand situations it is common to see any manner of cobbled together, broken or cheap and cheerful replacement test leads. The nonsense being that OH&S bureaucracy having many of these meters routinely being sent for expensive test and calibration sans leads.(note also that in every case when I've enquired there was minimal testing and no calibration involved in these OH&S tests. Merely a few automated tests against a reference source, an external only visual test and a very expensive sticker attached)In another thread here we have a bunch of apprentice brain surgeons extolling the suitability of the $5 meter. There is no way any of the lesser instruments stand up to the rigours of industry and and tribute to the Flukes etc above that they are remain operational. Equally there is no way of ensuring these cheap bit of rubbish are not at some times used on high energy circuits.This list is pointing out a lot of product that are overstating their safety and abilities, it is no guarantee that other correctly rated instruments are capable of their full ratings unless carefully maintained and handled. What we should do is also compile a list of instruments that do (when in good condition) deliver to their claimed specification particularly the lower priced examples.

author: Lightages
author_rank: Unknown
timestamp: November 03, 2012, 01:46:50 am
content: Quote from: Uncle Vernon on November 03, 2012, 12:19:32 amI am not sure that would be such a good idea. If we provide a list of "approved" meters, the $5 advocates might think they can do anything with them and have no danger. Someone might also find themselves the subject of a lawsuit when someone harms themselves using an "approved" meter that then fails. I would rather err on the side of pessimism when it comes to this. I have, however, provided a recommended list as I see it.

author: Unknown
author_rank: Unknown
timestamp: November 03, 2012, 02:02:48 am
content: Quote from: Lightages on November 03, 2012, 01:46:50 amI can see where you are coming from, and it's a pity the fanboys and those prone to jump towards litigation make it so difficult to offer and share helpful advice. Some up to date pass/fail/recommended lists in the wiki would be a valuable resource particularly for newcomers looking for advice, but I fear it would end as a fanboy mire where individuals seek to justify their death-trap of choice.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 04, 2012, 06:35:13 am
content: Extech is recalling selected EX612, EX613, EX622, EX623 digital clamp meters, as well as EX540, EX542 and EX570 multimeters, due to erroneous voltage readings with depleted battery.http://www.extech.com/instruments/recall2010.asp

author: Lightages
author_rank: Unknown
timestamp: November 05, 2012, 10:35:03 pm
content: This is exactly the kind of thing that discourages me from trying to make a list of multimeters that DO seem to meet their safety ratings.

author: LaurenceW
author_rank: Frequent Contributor
timestamp: November 09, 2012, 10:04:54 pm
content: Wow.So is the simple advice: "If you love life, buy a Fluke/Agilent, and look after it"?

author: Wytnucls
author_rank: Super Contributor
timestamp: November 10, 2012, 09:44:44 am
content: Quote from: LaurenceW on November 09, 2012, 10:04:54 pmNo, most of the accidents have happened with the best equipment available, often used incorrectly, in an industrial environment.The simple advice is "Know the limitations of your multimeter and be aware of the potential dangers before you connect your probes to anything"

author: nctnico
author_rank: Super Contributor
timestamp: December 26, 2012, 04:39:42 pm
content: I couldn't agree more. In (semi) industrial environments the circumstances are totally different. High voltage outlets, dangerous chemicals, etc. Over here it is mandatory to have a safety license before you can work in such environments. And still you may not get into every factory. Many years ago I had to work in a chemical factory. The least toxic stuff they had in there was Chlorine. Before anyone was allowed on the premises they had to take a safety course (covering handling toxic chemical spills, entering rooms, locking out parts of the plant, etc) and an exam. After taking the exam succesfully (score >90%) you'd get a safety passport which was valid for one year.

author: grenert
author_rank: Frequent Contributor
timestamp: December 27, 2012, 04:20:42 pm
content: If you want to check if a multimeter's (or any other electric product's) UL certification is for real, you can search at UL:http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/index.html

author: G7PSK
author_rank: Super Contributor
timestamp: December 29, 2012, 05:08:42 pm
content: Quote from: nctnico on December 26, 2012, 04:39:42 pmI once had to do some work at the DOW chemical factory in Kings Lynn Norfolk UK, this involved some welding for which I had to submit a safety sheet, on the sheet I stated that a portable welding generator was to be used, I got the contract letter back authorizing the welding with the condition that the power unit was diesel due to the concerns that a petrol powered welder may produce sparks from the engine. I don't know what they thought happened at the other end of the lead.

author: nctnico
author_rank: Super Contributor
timestamp: December 30, 2012, 02:23:10 pm
content: Safety wise it makes perfect sense to me. Most safety rules are based on lessons learned in the past. Where do you look at during welding? At the welding or the power unit? IOW: when something goes wrong what is noticed first and what is probably not noticed at all?

author: G7PSK
author_rank: Super Contributor
timestamp: December 30, 2012, 06:44:49 pm
content: They were worried about sparks igniting things the welding power unit is outside in the ope due to exhaust gases meanwhile the operator is inside the building full of combustible liquids up in the rafters welding brackets for an overhead gantry, showering sparks over everything with only a glass fiber blanket covering and they are worried about a spark from the ignition system and I have known diesel engines throw sparks out of the exhaust.

author: Ba1tuks
author_rank: Newbie
timestamp: March 23, 2013, 09:49:03 pm
content: The interesting thing in my experience is that cheap(not ridiculously cheap), 50-150 dollar meter isn't that dangerous as all of you speak. Ok, it blows inside, but if case is sturdy enough - nothing will ever happen to you. So stop that "if you wan't to live" crap :-) In 12 years I fried only one DMM, cheap, 40 buck one, when my HV PSU gone wacky and full 2KV 0,5A power to the output, and DMM was hooked up to it for more precise voltage setting. I have better DMM, agilent U1242B, very happy with it, but the death of cheap DMM only amused me :-D while the death of agilent would have knocked me on my knees screaming "why gog, why!?", pounding my head into the bench :-DYes, money has much bigger value for me now :-) Studying at university, zero parent support...

author: Lightages
author_rank: Unknown
timestamp: March 24, 2013, 03:30:29 am
content: I am glad you have never had a problem with a multimeter causing you harm. Most people, the majority, will never experience anything near dangerous happening with anything they do. This does not mean it does not happen. It just means it does not happen to almost everyone. There are real reasons why safety standards exist. That is because something has happened at least once to cause people to look at preventing it from happening again.I personally have seen a number of electricians walking around with burn scarred faces, missing fingers, and skin grafts. Yes that is an electrician and not a hobbiest. Electronics hobbiests are not likely to encounter the same conditions as an electrician. That does not mean that some hobbiest won't take his $5 meter and start troubleshooting his house wiring when he has a problem.The main thing is to be familiar with the potential problems and the capacity of your equipment to deal with problems and errors. That is where this list is to be used, to gain knowledge. If a piece of equipment is rated to be safe for something and it really isn't, I think it is better to know an be able to assess your risk. I really doubt anyone here will argue that not knowing is better.If you are paying for something, I also think it is better to know if you are getting what you think you are paying for. And if a company is willing to be outright dishonest about a safety rating, it is also highly unlikely that you get the other specifications you think you are paying for.

author: ConKbot
author_rank: Super Contributor
timestamp: March 25, 2013, 11:58:50 am
content: Quote from: Ba1tuks on March 23, 2013, 09:49:03 pm1KW power supply is much different than working in a breaker panel. Not everyone needs a cat III/IV meter, so evaluate your needs, and buy something that suits them If your meter is going to stay on your bench or in your car, and the only fault with the meter is no HRC fuse and no blast shields around the fuse/sockets, and it meets all your other needs and price point, sure, get it, enjoy your savings.While 240V wont arc-flash like like 480v, if youre probing in something like a panel and you get a transient that makes your chinese meter arc the 2mm between the input traces and it establishes an arc of vaporized copper and burnt paper-epoxy PBC, while the meter is in your hand... you may be needing new pants at best.Full disclosure is better than people being lied to and injuring themselves, its not a matter of "dont buy these meters" so much as "dont buy these and use them somewhere where you will need CATIII/IV" Though I'd prefer not to buy something where the manufacturer is lying about its capabilities, but thats up to each consumer.

author: Lightages
author_rank: Unknown
timestamp: March 25, 2013, 03:45:01 pm
content: Quote from: ConKbot on March 25, 2013, 11:58:50 amExactly. That is what I state in the first post:Quote

author: Wytnucls
author_rank: Super Contributor
timestamp: March 25, 2013, 05:24:27 pm
content: UEI DM5B500mA and 5A 250V fusesMax voltage 750V AC&DC

author: ConKbot
author_rank: Super Contributor
timestamp: March 26, 2013, 04:56:51 pm
content: Quote from: Wytnucls on March 25, 2013, 05:24:27 pm750V auto ranging, but only "500V protected" and 250V fuses. Marketing genius."ehh its good for 500, but you can probably get upto 750 without dying"

author: c4757p
author_rank: Super Contributor
timestamp: March 26, 2013, 05:05:36 pm
content: That kind of "it's possible, but it's not really" seems unfortunately common in the industry. I was just sifting through specs for ITEAD's PCB service and they say they do 6mil traces "8mil recommended" (i.e., "8mil traces, but if you give us 6mil we'll shove it through the DRC anyway").

author: Spawn
author_rank: Frequent Contributor
timestamp: March 26, 2013, 05:49:05 pm
content: Quote from: Wytnucls on March 25, 2013, 05:24:27 pmThat’s why I am trying to get one for a decent price, the shipment cost spoils it. Above all those statements it has only two lead inputs so far I could see on different images, so you are testing current till 5 amps and voltage till 500V at same inputs.I can understand all this fuzz about protection since the companies claim to have it so they should, but how many of you did measure anything higher than 400V in CATIII environment?I sure didn’t after 23 years as a Electrics field engineer, I am asking this because most people here are Electronics hobbyists, so do you really need anything which can measure higher than 400V protected and how many of those guys/girls have the education to do so? It is not only the meter you work with but the way you work is also important in those environments.

author: Lightages
author_rank: Unknown
timestamp: March 27, 2013, 03:53:03 am
content: Quote from: Spawn on March 26, 2013, 05:49:05 pmFull agreement from me. As I said, the information is presented as just that, information. Probably 99.99% of the people here do not connect to these conditions. Someone might, and while believing the rating on the meter. Information is never a bad thing. And again I say.... If the manufacturer is lying about one thing it is very lkely they are lying about other specs too.And FYI, I deal with 600VDC 10A circuits that can climb to over 1000V if not connected right. I think I want to be sure I have the right meter for the job. If not to protect me, at least to make sure my meter doesn't die while using it in this situation. Many meters I have seen would be outright dangerous to themselves or to me. What if the meter partially fails and shows no voltage and then I use that as a sign that it is safe for me to touch those wires? The safety of a meter affects many things.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 27, 2013, 08:05:49 am
content: Of course documenting these is good thing to do Lightages, nothing against thatI am referring to recommendations in other topics when a hobbyist ask what Multimeter to get, you, me and other handful professional members know what meter to get when it comes to work with high voltages. Our equipment at work gets yearly inspected.A hobbyist could do perfect with a Uni-T for example, still good build and accurate in “most” cases. If you ask me, a hobbyist shouldn’t even get near open rail systems and there won’t be any issues with most of those meters. If we have to work in those environments we need to dress up like we walk on the moon, let alone using a meter with suspicious protection.I won’t lie, I was looking for a cheaper alternative at work for the field technicians working for me, but as you know with Extech experience I got the search was finished right where it started. We will keep using Flukes. Alternatives like Amprobe, Agilent and Gossen Metrawatt won’t save that much financially and since I have good experience with Flukes when it comes to sturdiness we decided to keep working with Flukes, Amprobe could be little cheaper but I am not sure how long it will survive in Electricians toolbox.

author: Lightages
author_rank: Unknown
timestamp: March 27, 2013, 12:53:47 pm
content: Again we have an agreement. Most people here will never play with high energy. A UT61E will be fine for almost anybody on this forum. The TekPower TP4000ZC / Digitek DT-4000ZC that Frankie sells will be all that some need. Both are under $60. As far as the safety thing goes, I don't think we are necessarily overstating it because the reader at least now knows the difference and can now make a judgment based on this rather than blindly trusting the CAT rating a meter claims to have.BTW, I think you should give the BM257 a look for the cheaper alternative for the Flukes. Maybe just wait till Dave finally gets around to the shootout.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 27, 2013, 06:57:46 pm
content: It is to late, he has a Fluke 77-4 now. Maybe next guy who "loose" his DMM will get another one.

author: 2dfx
author_rank: Newbie
timestamp: March 31, 2013, 10:15:46 pm
content: Was wondering if I could chime in here with an investigation here of my own. Here in Canada, one company here called Canadian Tire sells DMM's under their Mastercraft name. I have a model here 52-0055-6 which is CATII rated, 1000V DC 750V AC. The fuses as you will see do not comply with this metric as it has 500mA & 10A 250V fuses.Album here

author: ResR
author_rank: Regular Contributor
timestamp: April 01, 2013, 06:06:45 pm
content: Elix M266. 750VAC 1000VDC rated and no fuseonly pair of resistors. How it got IEC1010 approval anyway, I wonder._

author: ivan747
author_rank: Super Contributor
timestamp: April 02, 2013, 03:12:00 am
content: Lightages, please see this thread about the AM-220 ceramic fuses -they are not HRC.https://www.eevblog.com/forum/testgear/amprobe-caught-using-fake-hrc-fuses/

author: Lightages
author_rank: Unknown
timestamp: April 08, 2013, 07:31:15 pm
content: Quote from: ResR on April 01, 2013, 06:06:45 pmSorry I didn't get back to this before. Actually, that meter might pass its CAT rating. It has no current testing using the the test leads so it does not need fuses. I really doubt it meets its CAT rating but it is not obvious. This is just another copy/rebrand of the very badly made generic "266" clamp meters. See:https://www.eevblog.com/forum/testgear/mini-review-teardown-generic-dt-266f-clamp-meter-aka-pos/So I cannot actually include this in this list but I agree this POS should be avoided.

author: Lightages
author_rank: Unknown
timestamp: April 08, 2013, 07:43:47 pm
content: Quote from: ivan747 on April 02, 2013, 03:12:00 amWell they not be HRC, but as already said they are not specified as such. No matter, that meter is not properly rated and so it goes on the list. I particularly hate the common current/voltage input jack as this is an accident waiting to happen. The reversed order of the jacks is also another disaster waiting in the wings.

author: maiakaat
author_rank: Regular Contributor
timestamp: April 29, 2013, 02:20:13 pm
content: Extech perhaps don't deserve to be given such a critical assessment.I have an EX510 with what looks like a revision 2 board, and better use of space around the probe terminals, with no possibility for any component to short.The Fuses are both 1000V SIBA HRCOne of the fuse mounts for the 0.8 Amp fuse looks soldered on the wrong way around, so they probably should really get rid of the factory they are using to resolve the remaining issues as it seems clear this is where the problem lies (and they may have done that by now as this is probably at least a few years old I would guess as it was old new stock I got cheap (under $50)It was also able to forward bios a white LEDThey really should use a better selector on the front though.

author: Lightages
author_rank: Unknown
timestamp: April 29, 2013, 07:47:27 pm
content: maiakaatPerhaps Extech might be trying to improve things. Technically many of their meters might meet their CAT ratings as does the EX510 in your post. I have listed the actual meters that I have reports of that don't but have made a sweeping statement n the rest because of all the reports of really bad quality control. Yours looks good but it has a fuse holder mounted backwards? That is still totally unacceptable and I think Extech needs to prove they have fixed things and people will not encounter anymore ridiculous issues before I will ever look at one again in the EX series. And really, you present one more example of an EX series that is made wrong instead of providing an example where nothing is wrong and say we should give Extech a break?

author: maiakaat
author_rank: Regular Contributor
timestamp: April 30, 2013, 07:31:39 am
content: Agreed, they do seem to be trying though, it would be interesting to see how their newest, most recently made products look.

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 05, 2013, 06:54:09 pm
content: I wonder how my old Fluke 75 would measure up to the laws these days out of curiosity that is

author: Lightages
author_rank: Unknown
timestamp: May 05, 2013, 07:14:42 pm
content: Well it is easy to see if it meets the labeling and component requisites. It does not say "CATX/XXXV" so it does not meet a technical spec. The fuses are not rated for the 1000V it has labeled on the front, so again not correctly built to latest standards. The rest looks good and it probably is better better protected than many other meters today. I would bet if you replaced the fuses with properly rated ones that it would pass the latest CAT ratings test for at least CATIII/600V.

author: tinhead
author_rank: Super Contributor
timestamp: May 19, 2013, 12:06:25 pm
content: Quote from: Lightages on October 27, 2012, 01:48:39 amuser manual speaks about "0.5 A/500 V & 10 A/600 V fast blow ceramic fuses", on the PCB you can clearlyread exact the same values, and they are of course installed as well. So where is the problem?

author: Lightages
author_rank: Unknown
timestamp: May 19, 2013, 05:22:36 pm
content: The latest CAT specs require that all input jacks be rated for the same rating. They also specify that any design or part of the meter must meet the maximum rating of the meter. In other words lower value fuses than what the meter is rated at may not be used. Technically it may have passed its rating tests under the older rules but it does not.It would also be much safer for the user to know that the meter has a lower rating on its current jacks without needing to remember it. It should have been marked on the face so that anyone picking up the meter can see.I am not saying that it is not a good meter, just that it does not meet current day safety requirements under the latest CAT rating rules.Quote

author: Spunky
author_rank: Regular Contributor
timestamp: July 13, 2013, 01:06:53 pm
content: All this fear about multimeters blowing up and I hardly ever hear anyone talk about fused test leads. Look in any sparkies tool bag and you'll find a bunch of HRC fused leads. I have probably £200-£300 of leads in my bag right now. Even a cheap meter can be made a lot safer by just changing the leads.Also my main meter is a clamp, so I will never have leads in the wrong jacks because they don't exist.That said I do make a judgement on what meters go in the electrical kit and what stays on the electronics bench based on what I see inside them.

author: Sigmoid
author_rank: Frequent Contributor
timestamp: August 03, 2013, 02:25:28 pm
content: I just blew a 500mA fuse on my BK Precision 2709b... Thankfully it originally came with a replacement in the package, lol!Anyway, since it's really easy to hamfist these into blowing, I'm out to get a replacement... Should I try to get a 1000V one in the same form factor? Any good sources for these?

author: Lightages
author_rank: Unknown
timestamp: August 03, 2013, 03:00:43 pm
content: Yes you can use a 1000V fuse. It will be an "upgrade" of sorts but it does not change the rating of the meter. It would be helpful to know where you are to give you place to buy the fuses.

author: Sigmoid
author_rank: Frequent Contributor
timestamp: August 03, 2013, 06:45:40 pm
content: Sorry, you're right. New York City, US. XD

author: Lightages
author_rank: Unknown
timestamp: August 03, 2013, 07:39:35 pm
content: Well you could call uphttp://www.tequipment.netand ask them. Or you can go tohttp://www.testequipmentdepot.com/amprobe/accessories/fuses.htmand select a fuse that matches what you want. You can also buy them on ebay.

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: August 03, 2013, 07:47:30 pm
content: Quote from: Sigmoid on August 03, 2013, 02:25:28 pmYes and yes.440mA.11A.Note there is a misprint on one of those pages. These fuses are meant to be able to interrupt 1KV *DC* without exploding, which is in a whole other league compared to the flimsy glass fuses we use for the AC mains. That is why they cost a bundle. Not sure if these fits your meter though.

author: rexxar
author_rank: Frequent Contributor
timestamp: August 10, 2013, 03:21:50 am
content: I'm sure this isn't surprising, but I bought an Elenco M-2666K multimeter kit that issupposedlyrated for 1kV. Unsurprising, there is no isolation slots on the PCB, and in fact there's about 5mm between the voltage input and the common trace. Same deal with the other Elenco meter mentioned here, there's a standard 250V glass fuse for the mA range, and the 20A range is unfused, though there's footprints for it on the board, which I populated because I had a holder handy. I wouldn't trust this thing for mains voltages, but I've got another meter for that, so it's okay. I can upload pics if anyone's interested.

author: madsci
author_rank: Regular Contributor
timestamp: September 22, 2013, 07:40:29 am
content: We can add the Mastech MS8229 and it's badge-engineered brother the Protek 6300.Claims CAT-III 600V and CAT-II 1kV but contains a 500V ceramic fuse like the Mastech 8218.I have not performed a thorough teardown of mine. I'll have to see if I can find it.

author: safetyfirst
author_rank: Newbie
timestamp: October 05, 2013, 04:17:21 am
content: Quote from: maiakaat on April 29, 2013, 02:20:13 pmThe EX510 is spec'd to handle 20A, but the pic shows a 10A fuse.

author: Lightages
author_rank: Unknown
timestamp: October 05, 2013, 05:16:27 am
content: Quote from: safetyfirst on October 05, 2013, 04:17:21 amThis is actually not a problem. 10A fuses will withstand 20A for a short time. Also, the amperage rating of the fuse is not an indication of its safety. What the fuse needs to do is break a current and voltage as defined in in the meter's CAT rating.

author: WhiteWolf
author_rank: Contributor
timestamp: October 07, 2013, 09:34:50 am
content: Quote from: Neilm on October 28, 2012, 05:16:10 pmIn Sweden and Finland, back in the 90's the real "CE" mark was a important thing on most of the electrical equipment for installation in buildnings and electrical/electronic equipment also. But then after 2000 it has becoming less and less important. And today I can see in stores, both in Sweden and Finland electrical/electronic stuff without the "CE" marking."OT: And even sometimes no safety markings at all on eletrical equipment for building installation."On my electronic engineer education at the university we got taught that the "CE" marking is just bullsh*t and we shouldn't even bother to look after it. Just because of the "China Export" thing. And when I worked at a well known company who are developing and producing car battery chargers. They went after the "CE" criterias but they didn't take them too seriously. Tuv and other criterias where more important to meet.

author: safetyfirst
author_rank: Newbie
timestamp: October 08, 2013, 07:17:16 am
content: According to the User Manuals and specs, all of the following Amprobe products are currently designed to 61010-1 2nd edition, but it appears that only the AM160a meets the 3rd edition (at least the fuse voltage req't on the A & mA/uA circuits).AM220 Cat3-600V but F1 & F2 are rated 250V (ding)AM240 sameAM250 Cat3-1000, Cat4-600 but F1 & F2 are rated 500V (ding)AM270 sameThe AM270 is a re-packaged Brymen BM817aAM140a Cat3-1000, Cat4-600 but F1 & F2 are 600V (ding)AM160a Cat3-1000, Cat4-600 with F1 & F2 rated at 1000V (great!)Based on the criteria used for the AM140a, then the AM250 and AM270 should be moved to the suspect list.I have a call into Amprobe about this awaiting a reply.But I am going to swap the fuses in my AM270 to 1000V versions.

author: delmadord
author_rank: Regular Contributor
timestamp: October 10, 2013, 06:08:33 pm
content: Probably known info but maybe it will be handy for someone:TENMA 72-7740 uses only glass fuses.

author: Lightages
author_rank: Unknown
timestamp: October 10, 2013, 07:09:49 pm
content: Quote from: safetyfirst on October 08, 2013, 07:17:16 amYou have valid points. Even the BM867 ha the same issue as the AM140 vs AM160. I sincerely believe that installing better fuses in this case brings them back up to spec. The lesser fuses must be a cst cutting measure for the less expensive model. I don't like it.The BM257 has a similar situation. The A fuse is rated for 600V but the mA fuse is only rated for 500V. Not a big discrepancy but till not right with the latest CAT rating requirements. I will be buying fuses to correct any meters like this to make them have the right fuses.With that being said, adding better fuses does not necessarily make the meter safer for higher voltages. The rest of the circuit board and design might fail at a lower voltage anyway.

author: Lightages
author_rank: Unknown
timestamp: October 10, 2013, 07:14:20 pm
content: The TENMA 72-7740 is a re-branded Uni-T UT60C. I have yet to see a Uni-T multimeter that probably meets its CAT ratings except for the German version of the UT61E and possibly the just recently released UT139C. All other Uni-T meters are suspect and are so are their re-brands.

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: October 15, 2013, 07:48:43 pm
content: Not sure if this has been mentioned on the forum before:This oldie but goodie videodemonstrates why the old hands try to instill people should buy a quality DMM for high voltage/high energy work. Video by VDE in Germany, recorded during a test for VDE certification. The meter failed the test.The meter manufacturer had marked the meter with a fake VDE certification mark without actually having the model tested by VDE. Yet that didn't prevent somebody else sending the meter to VDE for testing.

author: Lightages
author_rank: Unknown
timestamp: October 15, 2013, 08:34:27 pm
content: Thanks for that video link. I would like to know what voltage and current they used in that test.

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: October 15, 2013, 09:53:19 pm
content: No idea. There is a silly number of relevant DIN standards, and I don't have access to them. I'm speculating they used 1KV DC at a significant energy level (though less than 20kA), as that would be the most severe test while staying within CAT III spec.

author: Unknown
author_rank: Unknown
timestamp: October 15, 2013, 10:11:48 pm
content: IEC61010 calls for much larger transients. From memory I believe that a CAT III 1000 V meter should be tested with an 8 kV transient from 2 ohm source impedance. Not sure about the duration or charge. Fluke has a table in one of the app notes (ABCs of DMM safety?) on their website.

author: Lightages
author_rank: Unknown
timestamp: October 15, 2013, 10:37:31 pm
content: almYou remember correctly.

author: anwe
author_rank: Newbie
timestamp: November 03, 2013, 05:20:13 pm
content: The Brymen 820 series do not appear to meet their rating either.I did a quick teardown on my 827, and it has KTK-1 and KTK-10 fuses which AFAICT are rated for 600 VAC.I'm not 100% sure here, could it mean they meet the previous revision of the spec?The 820 series is listed in the manual as having 600 VAC fuses, so Brymen is completely honest about this fact.The 520 series do meet the spec according to the manual.The markings on the PCB indicates that both series share the same PCB, upgrading the fuses may be all that it takes if there are no differences in MOVs et.c.(all models 821-829 and 521/525 are listed with copper island indicators, there's a solder blob on the island matching the actual product number)./Andreas

author: chiefengineer
author_rank: Newbie
timestamp: November 03, 2013, 05:43:55 pm
content: PeakTech 2010 DMMCAT II 1000V ratedSelf recovery fuse 250V 200mA over current protector on milliamps rangeI have used my one for quite some time and it shows heat damage near the amps input jack. Maybe caused by some transistors on the milliamp range overheating.I don´t feel save using this.heat damaged casethe transistors next to the fuse may overheatedmore heat damage around these transistors

author: orjan-
author_rank: Newbie
timestamp: November 24, 2013, 03:22:47 pm
content: On the brymen BM867, the printed cat4 1000V rating on the multimeter is only for the V/ohm++ input. The manual clearly states that the A/mA inputs is rated for cat4 600V AC/300V DC. That's why the fuses are not rated 1000V. Many of the brymen multimeter's have different cat ratings for the A/mA input and the V/ohm++ input.From the manuals:BM867 Terminals (to COM) measurement category:V : Category IV 1000 Volts AC & DCmA?A : Category IV 600 Volts AC and 300 Volts DCA : Category IV 600 Volts AC and 300 Volts DCBM869 Terminals (to COM) measurement category:V / mA?A / A : Category IV 1000 Volts AC & DCBM857 Terminals (to COM) ratings:V : Category III 1000 Volts AC & DC, and Category IV* 600 Volts AC & DC.A / mA?A : Category III and Category IV* 500 Volts AC and 300 Volts DC.BM859CF Terminals (to COM) ratings:V / A / mA?A : Category III 1000 Volts AC & DC, and Category IV* 600 Volts AC & DC.TBM811, TBM812 & TBM829 Terminals (to COM) measurement category:V : Category IV 1000 Volts AC & DCmA?A : Category IV 600 Volts AC and 300 Volts DCA : Category IV 600 Volts AC and 300 Volts DCTBM811XEX, TBM812XEX & TBM525 Terminals (to COM) measurement category:V / mA?A / A : Category IV 1000 Volts AC & DCBM250(251,252,255,257) Series:Terminals (to COM) measurement category:V : Category II 1000V, CAT III 600V and CAT IV 300V AC & DC.mA?A : Category III 500Vac and 300Vdc.A : Category III 600Vac and 300Vdc.Link to some of the brymen manuals:http://www.brymen.com/product-html/0000-User/

author: Macbeth
author_rank: Super Contributor
timestamp: November 28, 2013, 08:50:22 pm
content: Pah. You kids with all your silly CAT3 600V/1000V etc multimeters. Back in the day we would use AVO 8 analogue multimeters, 20k ohm per volt. MASSIVE calibrated scale with mirror strip for parallax, absolutely no worries measuring mains or even three-phase. 2,500v AC/DC readings not a problem. Tested to 5kV. No silly fuses - a sprung cut-out button was all that was needed.My current AVO is a 1970's "Test Set No.1" which was a military spec and measures 3,000v AC/DC (and all other ranges are in the 30's instead of 25's). It can even read 30uA.Obscure Ever Ready cardboard box batteries only needed for the resistance ranges.We also worked on TV's and Radios that were all totally live chassis - no isolation at all. The highly (in)efficient voltages were all generated using a massive wirewound "dropper" resistor with taps for all the HV, LV, and finally the valve heater circuits. It was an electric bar fire in the telly. Yes, the metal chassis was directly connected often enough to 240V Live. More modern sets like the Philips G8 chassis (with the fantastic Nixie tube channel indicator) actually used high tech SCR chopper mode power supplies instead of the bar-fire dropper. Of course, no isolation, it was all live. Quite scary.Somehow I survived to tell this tale. You know what? I'm perfectly happy with my shitty cheap VC99.But for HV stuff I think I will just dust down that ancient Bakelite AVO 8 (Test Set No. 1).ETA: A link for anyone interested in good old school stuff.http://www.richardsradios.co.uk/testsetno1.html

author: Macbeth
author_rank: Super Contributor
timestamp: November 29, 2013, 06:09:07 am
content: Quote from: alm on November 28, 2013, 10:42:18 pmOh, I agree. Except the VC99 is too darn big to be holding in your hand anyway!. Come to think of it, I have never measured anything with a meter in my hand (even my shirt pocket sized super tiny autoranging DMM). I need my hands on the probes - the meter stays on the bench or wherever I can prop it up. Only clamp meters would be used in hand. But I don't do that sort of thing.But I have to say, I also would trust a massive 2-3kg AVO with bakelite case than any meter when playing with HT voltages! That is over any CAT III meter whether its Fluke or Chinese crap! That is what I implied in my previous post.Also, I think everyone should have an old fashioned 20k/volt analogue meter as well as an old fashioned 10-20MHz analogue scope. Why? Because they cost next to nothing and will end up in landfill otherwise - and you can learn so much more!

author: oldway
author_rank: Super Contributor
timestamp: November 29, 2013, 09:38:39 am
content: These ancient AVO are not as safe as you say:- same input terminals for voltages and currents: this is wrong and dangerous.- cut-out protection is very slow (actuated by pointer) and is not able to interrupt high energy and high voltage dc current.I repaired several badly damaged AVO 7 and 8. Not so safe at all.If you want to measure HV 5KV or more (in low energy circuits only !), it's a lot more safe to use a good quality HV probe.If you are a Electrical field engineer working with 600V high energy busbars or a Power electronics engineer (as i am), working with DC drives Edo 500V 5000A, you will not use a cheapy 5 bucks multimeter...only high quality multimeters as Fluke, Agilent, Gossens...

author: Lightages
author_rank: Unknown
timestamp: November 29, 2013, 06:34:53 pm
content: Quote from: anwe on November 03, 2013, 05:20:13 pmYou are correct and as orjan- has posted it appears that only the top models of the New Brymens actually meet their true CAT ratings according to the latest CAT requirements. As has also been stated it certainly appears that the only difference is the quality of the fuse fitted. The circuit boards are shared amongst these different models.

author: Lightages
author_rank: Unknown
timestamp: November 29, 2013, 06:44:46 pm
content: This discussion of old well built analog meters is interesting, but moot. They were designed for the times and with the knowledge and materials available at the time. They were also NOT CAT rated so they really have no place in this thread. I hope we can keep this discussion to modern available meters so as to help people select the right meter for their use.If someone wants to start a thread discussing analog meters specifically I will be happy to add a link to the main post to the thread. I am sure there are people who like to consider an analog meter and would benefit from opinions aimed at that topic and older meters in general.

author: calexanian
author_rank: Super Contributor
timestamp: December 01, 2013, 08:35:58 pm
content: There is something nice about a good VOM. Kinda like listening to a record warm fuzzy feeling kind of thing. It's part tool part artistic statement or something.Hands Off My Digital Fluke!!! Hahahahaha

author: TheBay
author_rank: Unknown
timestamp: December 21, 2013, 12:13:18 am
content: I have never seen a G8 with a Nixie tube!, would love to see one.I have worked on loads of Live chassis TV's back in the day, you could get a belt off the aerial socket on some sets if leaning against an earthed VCR lol! And idiots that put external speakers or headphone sockets on themQuote from: Macbeth on November 28, 2013, 08:50:22 pm

author: Macbeth
author_rank: Super Contributor
timestamp: December 21, 2013, 09:55:59 pm
content: Quote from: TheBay on December 21, 2013, 12:13:18 amIIRC the telly was one of the posher ones, and even had an ultrasound remote control. It had 6 channel buttons 3x2 (more than enough for future expansion! lol!) and a single Nixie that I guess only went up to number 6. Philips or Pye? So long ago... But yes, I only ever saw one of them.ETA: Those ultrasound remotes never did catch on, what with them sending the family mutt insane, and the TV picking up sounds like dropping dishes to change channels.

author: Lightages
author_rank: Unknown
timestamp: December 21, 2013, 11:46:14 pm
content: Please I ask again: Keep this thread on the topic. This is to be a resource for people to refer to and not have to go through completely irrelevant posts.

author: philpem
author_rank: Frequent Contributor
timestamp: December 23, 2013, 07:29:04 pm
content: DT830B - risk of electric shock due to insulation defects / risk of flashover, not compliant with EN61010 / LVD:http://unsafeproducts.eu/2013/09/13/digital-multimeter-dt830b-digital-multimeter/http://unsafeproducts.eu/2013/11/08/multimeter-%CF%88%CE%B7%CF%86%CE%B9%CE%B1%CE%BA%CE%BF-%CF%80%CE%BF%CE%BB%CF%85%CE%BC%CE%B5%CF%84%CF%81%CE%BF-digital-multimeter/

author: Lightages
author_rank: Unknown
timestamp: December 23, 2013, 07:38:23 pm
content: Thanks for the information Philpem. I already did put a general warning against these pieces of junk in an entry, "Any Meter with the model number "830"". There are people here on the forum that like them

author: don.r
author_rank: Frequent Contributor
timestamp: December 31, 2013, 09:20:26 pm
content: Quote from: philpem on December 23, 2013, 07:29:04 pmNobody should be surprised at this though.

author: AlienRelics
author_rank: Unknown
timestamp: January 06, 2014, 08:18:20 pm
content: No need to even mention Cen-Tech, then?

author: torr032
author_rank: Regular Contributor
timestamp: January 13, 2014, 03:11:08 pm
content: Quote from: philpem on December 23, 2013, 07:29:04 pmI saw these multimeters in Germany, in December 2013. In Toom Baumarkt stores, probably the Germany biggest stores for selling tools.

author: calexanian
author_rank: Super Contributor
timestamp: January 15, 2014, 06:02:46 pm
content: That is the Cen-Tech harbor freight meter. We break those apart and use them as panel meters in temporary setups, then throw them away! The harbor freight down the street sells hem for 2.99 every now and then.

author: rexxar
author_rank: Frequent Contributor
timestamp: January 18, 2014, 11:13:32 pm
content: I just bought a Uni-T UT203 clamp meter, and the input protection is... well, there isn't any. It's supposedly CAT2/3, but the only protection is a PTC. There's not even a fuse, so if something goes short while you're measuring mains voltage, you're going to have a very nice explosion.Blast protection is okay, there's rather deep walls, but I still wouldn't trust it. Additionally, there's no sort of isolation cutouts around the inputs, and a trace taps off the input and goes straight to the selector switch. I can see that arcing if you put a KV or two on it. (They also used a red wire to attach the common terminal?)Unfortunately, I'm stuck with it; being an unemployed college student, it's all I could afford, at around $40 on Amazon.

author: Lightages
author_rank: Unknown
timestamp: January 18, 2014, 11:39:05 pm
content: Actually the lack of fuses does not indicate that anything is wrong with the UT203. It is a clamp meter and fuses are only used for current functions. It might actually pass a full test according to its CAT rating but I doubt it.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 18, 2014, 11:51:03 pm
content: Quote from: rexxar on January 18, 2014, 11:13:32 pmActually, there's no need for a fuse. Basedhe input jacks do not measure current. This means the input impedance on these jacks will always be in the megaohm range. Current surge will not be a problem. So the lack of a fuse is expected.Based on the image I saw is rated CAT II 600C/ CAT III 300V. Based on the lack of current measurements on the input jacks and what I've seen of uni-t input protection this sounds a bit optimistic but far from unreasonable .So in summary, it sounds like your meter DOES NOT belong on this list.Sent from my EVO using Tapatalk

author: tzok
author_rank: Regular Contributor
timestamp: January 31, 2014, 02:26:29 pm
content: Quote from: philpem on December 23, 2013, 07:29:04 pmThese are VERY popular in Poland and are really cheap - you may buy them for less than 5€.

author: sean0118
author_rank: Frequent Contributor
timestamp: February 06, 2014, 10:15:10 am
content: Curiosity got the better of me while reading this thread, I took my cheap Digitech QM1523 apart. The 10 amps input is un-fused, but the "600V CAT II" input only has a glass 250V fuse. That's a bad thing right?Terrible soldering as well, only two of the four fuse holder legs are soldered to the board.

author: Lightages
author_rank: Unknown
timestamp: February 06, 2014, 05:44:49 pm
content: Yup that's pretty bad.Not only is only fused for mA and uses the wrong fuse for the CAT rating, it looks horribly built. The other glaring issue is that whoever designed the circuit board just designed it as if it were a small signal board. No consideration for voltages creepage or clearance. On top of that, there appears to be no input protection at all. Keep this one for the car and low voltage electronics and keep it away from the wall socket!

author: PedroDaGr8
author_rank: Super Contributor
timestamp: February 07, 2014, 02:12:30 am
content: Quote from: Lightages on February 06, 2014, 05:44:49 pmThis has to be one of the worst I have seen in a while! There is LITERALLY nothing between the 10A input and ground other than the CURRENT SHUNT!!!!!!That thing is BEYOND unsafe!

author: sean0118
author_rank: Frequent Contributor
timestamp: February 07, 2014, 11:13:47 am
content: Thanks for your replies, I thought that might be the case. I have only ever used it for low voltage DC and now that's all it will ever be used for.I found the manual and it does state that it has a 250V fuse, but then why mark it CAT II? I can't find the receipt, but these are still for sale atJaycar. I know this is a global forum, but anyone know if there is an authority in Australia to report this to?Also, it came with double insulated "CAT II" leads. Anyway to tell if these really are double insulated?

author: Wytnucls
author_rank: Super Contributor
timestamp: February 07, 2014, 01:12:02 pm
content: Quote from: PedroDaGr8 on February 07, 2014, 02:12:30 amGossen made a meter without a fuse on the A range (MetraHit 23S). It had a CAT II 1000V rating.Electrical Safety (23S only)Protection Class II per EN 61010-1:2001/VDE 0411-1:2002Measuring Category IIOperating Voltage 1000 VPollution Degree 2Test Voltage 5.2 kV~ per EN 61010-1:2001/VDE 0411-1:2002

author: PedroDaGr8
author_rank: Super Contributor
timestamp: February 07, 2014, 04:58:26 pm
content: Quote from: Wytnucls on February 07, 2014, 01:12:02 pmHow can you make that safe at 1kV? Maybe I'm just too much a noob but the though of 1kV across a 10mOhm shunt makes my hair stand on end.

author: Jasper
author_rank: Contributor
timestamp: February 12, 2014, 02:52:05 pm
content: Quote from: PedroDaGr8 on February 07, 2014, 04:58:26 pmAs far as I can tell it's basically irrelevant -- the Cat rating applies to the voltage jack, not to the amp jacks. It would be *really* frickin' hard to design a meter that could withstand on the 10A/20A fused jack (let alone an unfused version) genuine 1 kV at a fair few kiloAmps short-circuit-current power-distribution-network-grade electricity without breaking at all. Even getting a fuse to blow before any semiconductors or the shunt or the PCB traces do is not all that easy.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: February 12, 2014, 03:34:25 pm
content: Quote from: Jasper on February 12, 2014, 02:52:05 pmIncorrect, CAT applies to all inputs, though it used to be you could have different CAT ratings for each input. From what I understand, it doesn't have to survive per se. The meter has to be able to safely and fully break the current. Meaning no arc over. HRC fuses can break large currents at 1kV. So I'm not surprised that some can. Just not sure how you achieve the safe breaking without any input protection.Sent from my EVO using Tapatalk

author: Jasper
author_rank: Contributor
timestamp: February 12, 2014, 04:20:28 pm
content: Quote from: PedroDaGr8 on February 12, 2014, 03:34:25 pmAh:http://www.gossenmetrawatt.com/english/seiten/newsafetystandardiec61010-1since0.htmGossen claims that this has been the case since 2004. Since the meter in question is specced in the 2001 standard, it didn't yet have to conform to that.

author: mimmus78
author_rank: Unknown
timestamp: March 19, 2014, 10:54:07 pm
content: Hi everybody, good news for safety.I have on stock new revision of Brymen multimeters the BM257s and the BM867s. Brymen released the "s" version for all the multimeters series.Both models now uses fuses rated to 1000V to comply with third edition of EN 61010-1 and 61010-2-30, 61010-2-33, 61010-31 and in the "s" version all multimeters terminals have the same CAT rating.Tomorrow I will check what is changed "INSIDE" the BM257s and let you know.Ciao

author: mimmus78
author_rank: Unknown
timestamp: March 20, 2014, 09:34:39 pm
content: Here the two photos of the input protection board of the BM257(s) board:BM257BM257SThey made a lot of small changes to the board and used bigger PTC and Varistors. It seems an improvement over the pervious revision.

author: Lightages
author_rank: Unknown
timestamp: March 21, 2014, 12:49:17 am
content: I am very glad to see that. Franky............

author: Carrington
author_rank: Super Contributor
timestamp: April 18, 2014, 10:09:28 pm
content: Quote from: mimmus78 on March 19, 2014, 10:54:07 pmHi mimmus78!What has changed for the 867 series?Could you take a picture of the new board?ThanksCarrington.

author: mimmus78
author_rank: Unknown
timestamp: April 25, 2014, 08:58:14 pm
content: They (obviously) changed fuses with 1000V rated and a very light modification in resistors configuration of input protection.They are now using 4 resistors in 2x2 configuration instead of the 3 in the original circuit.Only thing "I didn't liked" much of old design was this resistor inside heat shrinking tube, maybe it was an afterthought and this last revision just corrected it.Good notice no other modifications where made in the other parts of PCB (no more insulation slots or traces) and this means old design was very good.Here attached an image of the PCB.->>>> ZOOM <<<<-

author: Carrington
author_rank: Super Contributor
timestamp: April 26, 2014, 06:19:57 pm
content: @mimmus78: Thank you very much.QuoteYes, without a doubt.I'll never measure over 1000V.

author: SeanB
author_rank: Super Contributor
timestamp: April 26, 2014, 06:38:06 pm
content: That is why I added the VDR's into my UT61E. Mine now clamps at 700 odd volts with safety. 2 275V varistors in series in each of the positions on the PCB

author: electron_misfire
author_rank: Contributor
timestamp: May 27, 2014, 11:55:47 am
content: I once bought a digitech QM1323 from Jaycar in Australia.Supposed Cat III/600v rating but only 250 volt fuses

author: WackyGerman
author_rank: Regular Contributor
timestamp: June 22, 2014, 03:29:59 pm
content: Well , I am an owner of the Greenlee DM 830A , the rebadged brother of the Brymen 829 and it has 1000 V HTC fuses inside . It costs 280 € but it has a lifetime warranty . Could also buy the Brymen 829 from Poland for roundabout the half prize but it only has 3 years of warranty and maybe also crappy fuses like all of the 820 series from Brymen . Well it also has the CE self declaration on it but the CE mark is less worth than the paint for the mark itself . It is still possible to get all the unsafe UNI-T and rebadged ones of them in Germany so electricians like me have to watch out not to get one of these shitty multimeter which could blow the ass off while measuring outlet sockets or something like that . For 0 V measurements on sockets and in distributions I prefer to use one of these 2 pole voltage tester for safety reasons ( for this cases I take the Fluke T150 )

author: ResR
author_rank: Regular Contributor
timestamp: October 03, 2014, 09:36:40 am
content: I have even worse multimeter I didn't added before for some reason - Velleman AVM 360. Blowed a fuse and a range resistor when accidentally got 230V to ohm's range. It has 1000VAC/DC measurement range but no way on earth I would connect it to that high voltages. The case is brittle as hell, no corrugated edges to contain the arc over, 5x20 glass fuse. It lights up a white LED with ohms measurement.

author: Puffie40
author_rank: Regular Contributor
timestamp: February 09, 2015, 03:58:22 am
content: Quote from: Lightages on October 27, 2012, 01:48:39 amI thought I'd crack open my EX520 (purchaced Dec 2013) to check the fuses and share a picture of the insides. Both fuses are rated at 1000v (), but they still have the caps and jumper wire at the input jacks.The glass fuse mentioned in the quote makes me wonder if the glass fuses appear because the assembler ran out of proper ones, so they just stuffed a "will fit" in to get it out the door.

author: SNGLinks
author_rank: Regular Contributor
timestamp: February 20, 2015, 04:17:24 pm
content: UNI-T UT60A bought in Maplins in the UKhttp://www.maplin.co.uk/p/uni-trend-ut60a-autoranging-with-pc-interface-digital-multimeter-n80cbMarked CAT III 1000V, CAT IV 600V and CE.Fitted with glass fuses rated at 250V.

author: naughtilus
author_rank: Contributor
timestamp: March 01, 2015, 02:36:48 pm
content: I've been a long time EEV Blog/forum reader and YT subscriber. As a hobbyist I educated myself thanks to Dave's and several other members here that input protection is very very important.The job of a multimeter is #1 to be safe for the user depending on application; #2 not to self destruct or damage the measured gear under normal operating circumstances; and #3 give accurate measurements, as the least important one. So I took all the "it must be UL listed" mantra to heart. For my own safety I wanted UL listed DMM as an assurance if it complies with IEC 61010-1 CAT ratings etc.So I went and checked what is the cheapest DMM that I can get that is also UL listed.QuoteSource:UL databaseHmmm. Wasn't Uni-T considered poo for safety and valid CAT ratings and no external certification, just slap that CE mark and sell by the boat load? It appears that all previous generation of Uni-T DMMs was UL listed. Go figure!TheUT60Ehas two glass fuses, one PTC, one spark gap package, no HV slots, cheapest jacks and cheapest leads. It says CAT III 1000V and CAT IV 600 on the unit. It got UL certified.In my hobby I work with amplifier PSUs, so there is moderate to occasionally high energy to deal with. I got kinda discouraged at taking UL listing as a decision factor for safety. I just looked at teardown photos and picked the Uni-T UT139C. It simply looked it had better input protection although not UL certified and only self rated at 600V CAT III. I considered Extech but to me Uni-T had better QC and therefore better build quality. I bought Fluke TL71 leads to replace the stock Uni-T ones and I think this is as safe I can get for $65.Is UL listing just a wank factor? I'm a bit confused.

author: JOE1234
author_rank: Newbie
timestamp: March 07, 2015, 11:32:52 pm
content: Regarding the BK Precision 2709B and its 500V rated fuses, here is the reply I received from BK:"The CAT III 1000V is rated based on the protective capability for the COM and V/Ohm input jacks which is protected up to 1000V. The 2709B meets the CE requirements."CE requests that the maximum measurement current must be marked on the meter, for example MAX 400mA, MAX 10A, or MAX 20A/30 sec. on the overlay around the input jacks. In addition, a symbol of exclamation mark (in triangle) is marked on the overlay to inform the user to read the instructions and the maximum rated voltage of Fuses in the manual. In CE regulations, CE does not request that the rated voltage of the fuses must be the same as the voltage of the CAT rating."If my interpretation is correct, BK appears to be offering a mere logical excuse rather than a substantive technical explanation. I wonder what rating UL would have allowed on the product--Cat II/III 300V?

author: miguelvp
author_rank: Super Contributor
timestamp: March 07, 2015, 11:55:28 pm
content: So I guess my UNI-T UT71B is really CAT III 1000 V

author: Lightages
author_rank: Unknown
timestamp: March 08, 2015, 12:25:03 am
content: BK Precision is WRONG. Simply wrong. If they don't understand the regulations, I would not be buying anything from them.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 08, 2015, 12:57:17 am
content: The latest IEC safety recommendations IEC61010 3rd edition 2010 are only enforced in Europe under EN61010 published in Oct 2010 and mandatory since October 2013.In the US, they were adopted later in October 2012 (UL61010) and will only be enforced from January 2018. So, in the US at least, multimeters can still be sold under the old regulations, where fuse voltage rating is not restricted.

author: Lightages
author_rank: Unknown
timestamp: March 08, 2015, 01:23:32 am
content: They refer specifically to CE standards, not US standards.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 08, 2015, 01:28:34 am
content: Quote from: Lightages on March 08, 2015, 01:23:32 amIn that case, the company should be made aware that EN61010 has changed since they last looked at it.

author: Lightages
author_rank: Unknown
timestamp: March 08, 2015, 01:32:02 am
content: Yes, I agreeAnd to quote the relevant clause:"101.3.2 Protection by a certified overcurrent protection deviceAn overcurrent protection device is considered suitable if it is certified by an independentlaboratory to meet all of the following requirements.a) The a.c. and d.c. RATED voltages of the overcurrent protection device shall be at least ashigh as, respectively, the highest a.c. and d.c. RATED voltages of any measuring circuitTERMINAL on the equipment."

author: miguelvp
author_rank: Super Contributor
timestamp: March 08, 2015, 02:33:03 am
content: For what is worth, the UNI-T UT71 series mention that they comply with IEC61010But their fuses are 250V as well (0.5A, 250V fast type fuse for the mili/micro Amp range & 10A, 250V fast type fuse for the Amp range)

author: Lightages
author_rank: Unknown
timestamp: March 08, 2015, 03:22:58 am
content: There are different revisions of IEC61010 and Uni-T maybe did actually meet an older version.

author: Neilm
author_rank: Super Contributor
timestamp: March 08, 2015, 06:24:43 pm
content: Quote from: Lightages on March 08, 2015, 03:22:58 amBut if it is still on sale in Europe, it must comply with the 3rd edition - the fact it was designed to meet the second edition before the 3rd was published is irrelevant.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 08, 2015, 06:50:18 pm
content: The version sold in Europe has been upgraded to meet the latest requirements. The PCB has been revised and it has the 1000V HRC fuses. Previous versions are now illegal, unless part of old stock imported before the deadline.

author: MoighonFweeman
author_rank: Contributor
timestamp: March 17, 2015, 03:19:18 am
content: QuoteI do agree with the statement that Extech does not quite meet expectations when it comes to quality control. However, it seems to me that the probes, and not the multimeter itself, are rated for those CAT ratings. Unless it claims somewhere in the documentation that the multimeter is also rated for up to 1000V? That would be silly.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: March 21, 2015, 06:32:47 am
content: Quote from: MoighonFweeman on March 17, 2015, 03:19:18 amWhere would you get that idea?If you look at this image, above the right jack you can clearly see CATIII 600V CAT II 1000V. So clearly that is what they claim the meter is rated for.

author: Tjita1
author_rank: Newbie
timestamp: April 11, 2015, 10:15:32 pm
content: UNI-T UT33A looks the same as the UT33C described in the list.

author: wertyq
author_rank: Newbie
timestamp: April 15, 2015, 03:29:47 pm
content: I don't think there is any way to tell what needs to be changed without torture tests

author: g0uli
author_rank: Newbie
timestamp: April 26, 2015, 01:04:33 am
content: Just purchased a Uni-T UT71C from a supplier in Germany. The internal construction is pretty much the same as every other Uni-T meter with the exception that two correctly rated ceramic HRC fuses are fitted and the board is screen printed with '1000v fuse' on the side. The Cat ratings on the front have been downgraded to Cat 3 600v and Cat 2 1000v, which looks about right, given the circuit layout. The leads supplied have a 2000v Cat 3 rating printed along their length and shrouded probes. As a professional electrician, I wouldn't have any issues using this meter on UK 240 volt domestic mains so long as it is firmly restricted to protected circuits on the output side of the fuse/circuit breaker box. Overall the construction seems adequate to contain any problems inside the meter casing so long as it is used within its design limits. Overall a decent 5 digit 40,000 count meter for not a lot of money and obviously built to a better standard for the German market.I bought this meter primarily for low voltage hobby purposes and the USB data logging ability. I have a proper calibrated Cat 4 meter for professional use.

author: meeder
author_rank: Regular Contributor
timestamp: June 29, 2015, 09:40:02 am
content: http://www.elro.eu/en/products/cat/electronics/installation-material/meters1/universal-multimeterElro M970 multimeter. Lists CAT II 600V on it but only has 250V fuses.Any guess on which manufacturer is making this thing?User manual:http://www.elro.eu/uploads/products/manual/M970_Manual.pdf

author: Lightages
author_rank: Unknown
timestamp: June 29, 2015, 07:32:12 pm
content: That is a Mastech.

author: tautech
author_rank: Super Contributor
timestamp: July 03, 2015, 09:34:12 am
content: Whilejoeqsmith's handheld DMM surge tests are not in a certified lab, should they not be linked to from this thread?https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/

author: Lightages
author_rank: Unknown
timestamp: July 03, 2015, 03:22:23 pm
content: While I agree that joeqsmith's tests are very interesting and teach quite a bit, I am not sure that they actually relate to multimeter safety standards. hey certainly show how certain multimeters can fail to operate after such testing and that should be a consideration when buying a multimeter. I am in the process revising the first post of this thread and probably will include a link to his videos and his thread but I want to clarify the requirements of the IEC about whether the meters need to survive completely or just not present a hazard to the user. This is still the big question.

author: Wytnucls
author_rank: Super Contributor
timestamp: July 04, 2015, 10:42:37 am
content: From Fluke's notes:The International Electrotechnical Commission (IEC) established safety standards for working on electrical systems. Make sure youare using a meter that meets the IEC category and voltage rating approved for the environment where the measurement is to bemade. For instance, if a voltage measurement needs to be made in an electrical panel with 480 V, then a meter rated CategoryIII 600 V or 1000 V should be used. This means the input circuitry of the meter has been designed to withstand voltagetransients commonly found in this environmentwithout harming the user.Also:Special DMM overload protection prevents damage to both the meter and the circuit, while protecting the user.

author: jimdeane
author_rank: Regular Contributor
timestamp: September 10, 2015, 03:45:13 pm
content: I have liked Extech products since buying a thermal IR thermometer from them years ago. I saw Dave J recommended it, so I bought it and an mn35 as a second/travel meter.Dave J didn't seem to make a fuss about the fuse rating in the video. Did he not think it was a concern?

author: steve207a
author_rank: Contributor
timestamp: October 31, 2015, 05:59:55 pm
content: Himany modern multimeters suffer from the modern age of shrinking everything down using the smallest case and components which in itself means isolation and protection suffer. Often the test leads are flimsy the wire gauge is suspect. fused test leads seem to be not an option nowadays . Old equipment was larger and bulky did not carry any CE mark or extra safety standard it was just built well to do the job .It did ohms volts and amps and that was that. nowadays they do cap testing, frequency, transistor testing ect seems the basic meter part is forgotten.when buying a test meter some common sense is required to match it to the job inhand forget CE marks ect use your own eyes and common sense and dont put a thin scrawny meter on anything over 12volts CE marked or not HA HA BOOM!!

author: allikat
author_rank: Contributor
timestamp: December 03, 2015, 10:52:41 am
content: Uni-T UT58 series (various models are delineated by screen print changes and new switch board). CatII/Cat III rated, with 1kV range DC, 750V range AC. One small 250V rated 0.5A glass "Fast blow" fuse on mA range, 10A range unfused.Bets on how quick a newb can let the magic smoke out?PS: This forum really needs an escaping magic smoke smiley.

author: allikat
author_rank: Contributor
timestamp: December 06, 2015, 12:58:31 pm
content: Quote from: Wytnucls on March 08, 2015, 06:50:18 pmPlenty of old stock floating around Europe sadly. Maplins in the Bristol area did not have any stock with HRC fuses. Started with a UNI-T 58A, swapped it for a 60E as I had need of a meter urgently. Nearly said upgraded - lol. There seems to be space on the board, and contacts available to swap the 10A fuse to something more sensible. When I've got a workable soldering iron, I'll pick up a surface mount UK style fuse carrier and swap it in. It won't be full HRC but it'll be a ceramic fuse at least, and better than the pissant glass thing.

author: crispy_tofu
author_rank: Super Contributor
timestamp: December 07, 2015, 01:40:46 am
content: Quote from: allikat on December 03, 2015, 10:52:41 amclose enough?

author: allikat
author_rank: Contributor
timestamp: December 07, 2015, 05:28:09 am
content: Quote from: crispy_tofu on December 07, 2015, 01:40:46 amPretty close.

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: March 18, 2016, 01:31:32 pm
content: Velleman DVM1090DMM (PCB inside says MASTECH MS8201H)Marked with 1000V CATIII, 600V CATII, Fuses are rated at 250V (also the ceramic factory installed fuse appears to me as a slow blow, rather than the specified fast blow). I think insufficient track spacing for creep even at 600V, let alone 1000V. Poor soldering all around with many blobby soldering (the current shun was totally missed on the backside!). Improper strain relief on probes. Can't see much on input protection, nothing too fantastic I think.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 10, 2016, 10:00:35 pm
content: https://www.eevblog.com/forum/testgear/ut70b-pcb-photo/Unitrend UT70B

author: System Error Message
author_rank: Frequent Contributor
timestamp: June 20, 2016, 02:48:11 pm
content: This is a very helpful thread. I have a VC99 multimeter and according to this thread i should open it and move things further apart inside? Also saying its not rated for mains voltage but it will do fine for your everyday 5V and 12V? If i just replace a fuse would it than be safe to use it for mains voltage?So whats the danger with getting one of these multimeters and using them on your everyday small electronics like arduinos?

author: Simon
author_rank: Unknown
timestamp: June 20, 2016, 04:46:32 pm
content: Quote from: System Error Message on June 20, 2016, 02:48:11 pmAvoid this meter, it's awful. An amprobe at the same price will werve you better.

author: System Error Message
author_rank: Frequent Contributor
timestamp: June 21, 2016, 12:11:53 am
content: even amprobe is on this list and extech, both meters which people recommend. How on earth do we get a meter when they're all on this list?

author: PedroDaGr8
author_rank: Super Contributor
timestamp: June 28, 2016, 01:30:04 pm
content: Quote from: System Error Message on June 21, 2016, 12:11:53 amBy doing their homework. Every company has dud models (even Fluke has had a few).Amprobe has two models which are duds and loads of models that are safe and reliable. Even then, the two duds might have been updated or EOL'd I am not sure.Very few ppl recommend Extech anymore, their QC is quite bad and getting worse. You just have too see Joe Smith's comparison of new versus old Extech.

author: joeqsmith
author_rank: Super Contributor
timestamp: June 28, 2016, 01:40:41 pm
content: What products does Fluke currently offer that you consider duds and why?Quote from: PedroDaGr8 on June 28, 2016, 01:30:04 pm

author: PedroDaGr8
author_rank: Super Contributor
timestamp: June 28, 2016, 01:44:08 pm
content: Quote from: joeqsmith on June 28, 2016, 01:40:41 pmI used past tense "has had", currently while I am not a fan of the 11x series I think calling it a dud would be a huge exaggeration. I am referring to some issues they have had in the past. One example being their ill-fated first attempt at outsourcing production to China with one of the 77 series meters. It was a huge dud and is well known for not even being CLOSE to Fluke's standards. It tended to drift, had build quality issues etc.

author: mikerj
author_rank: Super Contributor
timestamp: June 28, 2016, 05:20:33 pm
content: Quote from: System Error Message on June 20, 2016, 02:48:11 pmThere's no real danger at all in using them for low voltage, low current stuff. About the worst that's likely to happen is having bad readings caused by crappy sockets and probes etc. or having such a high burden voltage on mA range that your circuit fails to work.

author: mos6502
author_rank: Frequent Contributor
timestamp: October 03, 2016, 09:56:16 pm
content: Quote from: System Error Message on June 20, 2016, 02:48:11 pmThe danger is that one day, maybe you or someone else forgets about how dangerous this meter is (since it nonchalantly says "1000VDC" on the front) and decides to measure some stuff on a breaker panel, resulting in a one way trip to the morgue or at the very least the nickname "Mr. Crispyfingers".

author: Mek
author_rank: Newbie
timestamp: October 04, 2016, 08:40:40 pm
content: Quote from: Lightages on October 27, 2012, 01:48:39 amI have this one. Thanks for this information. One little point: it's "Vici", not "Vichy"

author: Macbeth
author_rank: Super Contributor
timestamp: October 09, 2016, 10:13:11 pm
content: Quote from: Mek on October 04, 2016, 08:40:40 pmYour's might be, but mine isVichyVC99. I think they had to change to Vici after learning that Vichy = Nazi collaborators in France and want to sell their meters over in the EU. Of course more realistically is someone else has pirated the IP and modified it a bit and went in to production as yet another "Fluke competitor" but also riding on the coat-tails of Vichy.

author: baastrup
author_rank: Contributor
timestamp: December 08, 2016, 12:27:07 pm
content: How about uni-t 139c is that oki?

author: Lightages
author_rank: Unknown
timestamp: December 08, 2016, 06:32:16 pm
content: Quote from: baastrup on December 08, 2016, 12:27:07 pmThe UT139C seems to be a fairly well built meter. Uni-T claims it meets IEC/EN 61010-1 with a CAT rating CATIII/600V. It is possible that it might actual meet these standards, but Uni-T has not provided any third party certifications. Given that Uni-T has rated many models with CAT ratings that are obviously not possible and the UT61E was redesigned and derated at the same time so as to be able to be sold in Europe, I would err on the side of assuming that the UT139C doesn't actually meet the ratings until proven otherwise.Having said that I would still recommend this as a decently protected meter for general electronics and home electrical work. I would not use it in a CATII environment though. You can also see tests done by Joe Q Smith here on the forums. He has been torturing many meters to see how they stand up but remember his tests are not confirmation nor disproof that any meter actually meets a specific CAT rating. Some of the failures show that some meters are obviously rated falsely but his tests are not official.

author: trantula
author_rank: Newbie
timestamp: August 29, 2017, 09:12:31 pm
content: Best safety spects ever watch and learn..That is how the job is done........

author: dinoboy
author_rank: Contributor
timestamp: August 30, 2017, 01:52:48 pm
content: Quote from: Lightages on October 27, 2012, 01:48:39 amI don't know how to test the safety of the European version but i do trust the lower ratings certified by the German Professionals:https://www.eevblog.com/forum/testgear/uni-t-ut61e-multimeter-teardown-photos/msg1291236/#msg1291236"complete unknown" maybe to you. Just ask the 2 institutes about the European version. They tested the safety, they certified the safety.They will know.Good luck.Bye.

author: Pawelr98
author_rank: Regular Contributor
timestamp: April 21, 2018, 11:05:09 pm
content: Quote from: trantula on August 29, 2017, 09:12:31 pmIt's just how things are in this part of the world.This is my cheap digital meter. I paid 19PLN for it.This was around 5USD at the time.Vacuum tube radio transformer. Anode windings in series (2x300V in series but also 250V into 220V primary).Usually I use this meter:1970 Mera UM3a1% accuracy for DC range, 1.5% accuracy for AC rangeAC range is a bit borked (most likely the oxide rectifier is done) so I don't really use it for AC measurement (other than current range where I have a certain correction ratio).

author: najrao
author_rank: Regular Contributor
timestamp: April 30, 2018, 10:46:23 am
content: Since there must be literally millions of unsafe multimeters out there, it occurs to me there is a case for some enterprising guy to come out with "pluggable" high rupturing capacity fuses, which just attach at one end to the 10A or xxxmA sockets on the meter. The internal fuses can then be replaced by links.The other end could be a high quality probe lead. Such a source could also be an answer to the extortionist price charged by the original manufacturers for replacement fuses.The V-ohms-*** connection should not need separate fusing, as it is almost always protected by current limiting elements.This may not address all the lack-of-safety issues, but may be accepted by quite some safety conscious users.

author: ChrisLX200
author_rank: Unknown
timestamp: April 30, 2018, 11:04:18 pm
content: Quote from: najrao on April 30, 2018, 10:46:23 amYou can buy probes with a built-in fuse.

author: Gyro
author_rank: Super Contributor
timestamp: May 21, 2018, 10:25:37 am
content: Amazing how easy it is to meet CatIV 600V on Amazon these days!https://www.amazon.co.uk/SURPEER-Multimeter-Digital-multimeter-Voltmeter/dp/B073VLL33N/

author: exit_failure
author_rank: Regular Contributor
timestamp: June 30, 2018, 10:04:59 am
content: Quote from: Lightages on October 27, 2012, 01:48:39 amBrymen apparently upgraded the fuses in their BM867s. I got mine this April from welectron and it had proper 1000V rated Bussmann fuses in it. (DMM-B-11A and DMM-B-44/100R)

author: Specmaster
author_rank: Super Contributor
timestamp: July 31, 2018, 08:29:49 pm
content: Quote from: exit_failure on June 30, 2018, 10:04:59 amJust checked the fuses in mine and I can confirm that are 1,000v rated as well, I really love this meter it is well worth anyone looking at this as a real serious meter and anyone overlooking it is seriously burying their head in the sand.

author: AceAK
author_rank: Newbie
timestamp: August 13, 2018, 08:25:14 pm
content: Hi everyone,As I was reading through the thread, I realized Uni-Trend/Uni-T multimeters keep popping up quite frequently. The company, in general, received a pretty bad rap and users were advised to avoid using Uni-T multimeters for mains voltage.What I found was pretty surprising. Uni-Trend actually has so many of their DMMs tested and listed, while not under UL, but under yet another pretty reputable lab - ETL. The link is here:https://ramuk.intertekconnect.com/WebClients/ITS/DLP/products.nsf/4c8700f3b75987a08525777700583333/f75b2aea8bd09b8a862582dd0024a320?OpenDocumentEven the Uni-Trend website provides the certificate proofs. I did a check on UT139C on their website and clicked Download Manual, then clicked UT139C ETL Certificate. Pretty convincing document there.If ETL says it is safe, it is safe, right? But I also took into account the previous negative comments about Uni-Trend in this thread and could not help but wonder could we really trust the independent laboratories (incl. the reputable ones) for Uni-Trends' or anybody's CAT Ratings for that matter. However, even Dave Jones chose to use ETL for his Brymens. So...well, I am confused.I don't think Uni-Trend would pay so much money to ETL just to change to lower quality components for their multimeters downstream merely for higher profit margins. Even if Uni-Trend engages such cost-cutting approach, ETL for sure will whack them hard if their reputation is compromised by Uni-Trend. At the end of the day, it just does not make any business sense for Uni-Trend to do so.And if Uni-Trend really upholds their listing standards and the independent laboratories could be trusted, could it be that the previous analysis of their multimeters not being safe is mistaken, at least partially so?Hope to hear all your views.Cheers.

author: joeqsmith
author_rank: Super Contributor
timestamp: August 14, 2018, 02:55:32 am
content: Take a look at the UT61E for example. The link you provide lists it. If you do a search on this site, you will find more than one flavor of this meter. There are some major differences between them. After you look into this, ask yourself if you feel that all of these different flavors of the 61E are actually certified and if so, how come they add so much cost to one flavor of it rather than just making more profit. If you check the price, you will find a fairly large difference. If you come to the conclusion that some of their UT61Es may indeed have been certified and others not, ask yourself how do they get away with it and what's really the point of the certification if you can't trust it?Do you think the lower end companies do any sort of annual inspection of their product? Or do you think there are companies that will get a product certified, then change the design over and over, maybe to reduce cost, and never have it certified again. Would you have a problem with this?

author: AceAK
author_rank: Newbie
timestamp: August 17, 2018, 07:46:39 pm
content: There is inevitably a conflict of interest, I supposed. After all, companies pay the independent laboratories to test their products for certifications.But if independent testing laboratories such as UL and ETL are accorded OSHA's (Occupational Safety & Health Administration) recognition as NRTL (Nationally Recognized Testing Laboratory), it is not impossible for the government to enforce the labs to deny certification testings to companies which have been suspected or guilty of changing their components after being certified, where failure to do so may result in their OSHA's recognition being revoked. The lab could also revoked the certification given to these companies' products. The labs would naturally only do that if they value their OSHA's recognition more than the paychecks from their customers. Not sure if I am being too naive or harsh here.Of course, the companies may argue that lemons may exist in their certified models. But it was pretty obvious of Uni-Trend's non-compliance when there were so many reviews/reports of their European UT61E batch being constructed differently than the Asian UT61E, which had worse components but received better CAT ratings. Cough cough, ETL...so much for being OSHA's NRTL.The issue is there is no real "policeman" at the moment. Therefore, I support the calling out of dubious CAT-ratings meters in this thread as a more direct move rather than waiting for the government to stretch its heavy bureaucratic hand in this matter. May the market forces lead the Chinese manufacturers to the right path.With that being said, we must realize a large portion of the electronic hobbyists don't see the risks of using Chinese meters as they usually deal with low voltages - a point which I may not totally agree but can understand. The price margin between a brand name (US/German/Japan ones) and the Chinese ones is a huge factor. Can the pricing of brand name products ever compete with the Chinese ones? I believe they can to a certain extent, given their insane markups. But I doubt they would want to, given the investors-heavy burden of these brand name companies. The Chinese companies have less of such problems as they based their profits on volume sales.From what I see, the consistent comment here is "Cheap multimeters have their place but I would only trust my properly-certified meters for mains". In other words, the users buy both the cheap and expensive meters for different uses and the companies win. The market's desire for safer Chinese meters and cheaper brand name meters seems to be generally ignored. From the Chinese market, so far, only Uni-T has less than a handful of more believable CAT-Ratings meters like UT139C. I wonder why. Fluke has only caved in a bit to the market producing lower-priced Chinese meters. However, the price margin is still quite apparent to many. Brymen is so successful in this forum possibly due to the battle between the typical brand names vs Chinese companies and of course, due to our Dave Jones. I don't know how much the companies listen but the least we must do is speak. So kudos to all those who contribute to this forum and Youtube (sadly, not available in China).

author: rsjsouza
author_rank: Super Contributor
timestamp: August 17, 2018, 08:39:55 pm
content: Quote from: AceAK on August 17, 2018, 07:46:39 pmThere is a difference between being tested and certified and carrying a "mark" on its meters. The test and certification is a "point release" deal - i.e., they certify and test samples of the product (all provided by the manufacturer) against a specific regulation and write up a document that covers the methods used and the standards tested. That's it. No further relationship between the two companies. That costs real $$$ once.When the product carries a "mark", it is fully "listed" - i.e., during the time the listing is valid, the certification agency will re-certify the products released by the manufacturer from time to time to be sure the listing is still valid. Also, IIRC the manufacturing plant will also receive inspections from the certification agency to guarantee this still meets the conditions when the first inspection took place. That costs real money over time.What happens is that it is not really uncommon for manufacturers slip on quality or reduce costs to the point of maintaining minimum functionality - especially if they are operating in the ultra low margin markets. If their product is liste, they are forced to maintain the quality and functional aspects of the product.A government could in theory enforce the companies to refrain from doing business with regular offenders, and I am pretty sure they do for the really bad ones (thus the slew of false markings around), but I suspect the interest rapidly diminishes given the overall market is really much larger than the offenders. Also, the leverage rapidly diminishes since several of these companies are foreign to their markets and the certification agencies' headquarters (that is one of the points that Señor Frump is trying to bring to the table with the recent brouhaha on international trade tariffs, but I digress).

author: GreenHW_GUY
author_rank: Contributor
timestamp: October 30, 2019, 04:00:55 am
content: why can a cheap china junk multimeter end up on 1. place and a okay Fluke multimeter end as a 10. place herehttps://www.smarthome.guide/best-multimeters/

author: AVGresponding
author_rank: Super Contributor
timestamp: October 30, 2019, 05:35:36 am
content: Quote from: GreenHW_GUY on October 30, 2019, 04:00:55 amThe numbers only represent the order they looked at them, not the order they placed.They gave each one an individual 'award'.The Fluke 87V was awarded 'Best professional' multimeter.Still, I will agree that they didn't seem to question the safety ratings of the cheaper offerings, and just accepted the manufacturers self-assessment, which most of us here know are often pure fantasy.

author: HKJ
author_rank: Super Contributor
timestamp: November 05, 2019, 03:58:50 pm
content: Quote from: GreenHW_GUY on October 30, 2019, 04:00:55 amProbably because that brand payed the most.

author: Specmaster
author_rank: Super Contributor
timestamp: November 07, 2019, 12:15:13 am
content: Quote from: GreenHW_GUY on October 30, 2019, 04:00:55 amI think the name says it all, smarthome, it is a guide aimed at the average DIY'er at home where bang per buck comes into play and they are not going to pay for the extra protection etc that a Fluke meter is going offer over a cheap meter that will do the same perceved job but at a far greater risk to both the meter and the user in the event of something going. You just are not going to find on the cheap chinese / far east meters in any proffesionals tool kit.

author: EEVblog
author_rank: Unknown
timestamp: November 07, 2019, 02:02:19 am
content: Quote from: rsjsouza on August 17, 2018, 08:39:55 pmOnly for regulatory compliance marks like RCM/C-Tick mark here in Australia, or FCC.UL and ETL are private industry marking that the government does not regulate. UL or ETL would have to privately sue a company for trademark infringement. Although they could potentially get customs to stop product with Trademark infringing label from being imported perhaps.

author: JPNH20
author_rank: Contributor
timestamp: February 04, 2020, 03:33:31 pm
content: Here's the answer to your question, which is buried, in the websites T&Cs:Amazon Affiliate Programwww.smarthome.guideis a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.The Chinese company is paying a higher commission on purchases from affiliates who drive traffic to the product on Amazon. I worked on this type of thing around 2010. Basically there's an equivalent to eBay, for lack of a better example, where companies bid against each other for higher affiliate payouts. The affiliates then choose who has the best payout and drive traffic to the product in hopes that someone make a purchase and they receive their affiliate commission. If you do some Googling around there's tons of these review sites for all kinds of products in top ten formats so they can maximize the chance of a purchase and affiliate commission while still looking legitimate and not putting too many choices in front of the user. A law was passed a few years ago that they now have to disclose the fact they may earn a commission because it was becoming the wild west. However it's usually buried in a disclaimer or T&C statement.

author: KD2FVM
author_rank: Contributor
timestamp: February 04, 2020, 05:28:44 pm
content: I thought the safety rating of the meter and leads (600V for example) meant that the user would be safe connected to (and protected from) voltages that high, not that the meter could measure that level. That said, a 250V fuse would be appropriate if the meters range was 250V and less. The fuse is to protect the meter, safety rating or class rating is an insulation safety rating and measure of dielectric strength.

author: AVGresponding
author_rank: Super Contributor
timestamp: February 04, 2020, 06:20:18 pm
content: The fuse rating of 250V is a bit odd, when you find it in meters supposedly safe for measuring at higher voltages.The fuse of course only sees a much smaller voltage, in normal conditions. However, in the event of the fuse blowing due to overcurrent, both the voltage rating and the breaking capacity come into play.Essentially, the fuse only meets its breaking capacity if it's operating within its voltage range. Use it outside that range and you're going to get reduced protection.In reality you're only going to see voltages larger than that if you make a mistake measuring current in a mains voltage circuit or similar.I wouldn't trust or use a meter that has this type of fuse for this measurement.

author: joeqsmith
author_rank: Super Contributor
timestamp: April 04, 2020, 06:34:18 pm
content: Some videos on multimeter safety.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 03, 2020, 02:34:23 pm
content: Looks like he has a new video on safety.

author: rsjsouza
author_rank: Super Contributor
timestamp: May 03, 2020, 06:30:01 pm
content: Funny the issue with the decimal point on the Amazon meter. I just received my Fluke 101 that is missing both resistance multiplier indicators (M and k). I am working to convince the seller this is actually a defect.

author: exit_failure
author_rank: Regular Contributor
timestamp: June 23, 2020, 10:12:54 am
content: Quote from: joeqsmith on May 03, 2020, 02:34:23 pmI think that what he says in his video is wrong or at least dangerously incomplete: Having a device tested by a certified testing house is fine and dandy but what's really important is what norms and standards it has been tested against. UL or any other similar testing institution will only do the test you ask them to do. So being UL listed may for example only mean that they tested it for environmental or fire safety or but not electrical safety and then the CAT rating may just as much be a lie as for any 5 dollar meter from aliexpress.That means that the really important step is not finding the meter in some database but looking at the tests they actually performed.edit: spelling and last sentence

author: Lightages
author_rank: Unknown
timestamp: July 08, 2020, 01:11:24 am
content: What one needs to keep in mind when thinking about multimeter safety is if it has a rating is that it actually has a testing house proof of its safety. CE is useless IMHO. Anyone can place CE on their product and all they are doing is hanging themselves out for liability should it actually not pass the CE directives.Some countries don't care or worry about the liability so it is a useless certification. If a product has a TUV, UL, CSA, or some other certification then the records of what criteria has been tested are available for the asking. This thread was started to help people understand the differences between safe (or safer) meters and pure BS. I am glad that has raised some awareness.Oh yes..... I am back!

author: tautech
author_rank: Super Contributor
timestamp: July 08, 2020, 01:24:25 am
content: Quote from: Lightages on July 08, 2020, 01:11:24 amAnd nearly 2 years since you posted last.Settled back in the GWN ?

author: Lightages
author_rank: Unknown
timestamp: July 08, 2020, 01:58:36 am
content: GWN, Great White North? I am worried about that phrase right now.....I was getting bored with my new 9-5 life so I decided to get active again. There will be videos!

author: rsjsouza
author_rank: Super Contributor
timestamp: July 08, 2020, 02:43:02 am
content: Welcome back, Lightages! You were missed.

author: Lightages
author_rank: Unknown
timestamp: July 08, 2020, 09:20:44 pm
content: Thanks. I missed my interactions here too.

author: dylanmitchell
author_rank: Contributor
timestamp: December 04, 2020, 11:36:07 pm
content: What companies always meet or exceed listed specs? Fluke, Agilent/ Keysight? Others?Didn't see Fluke on the list but Amprobe was on there.

author: Lightages
author_rank: Unknown
timestamp: December 05, 2020, 02:37:43 pm
content: If I were to try to name the companies that always meet listed specs, it would be a very short list. I would say, with reservation, that you could basically pick up an new meter from Fluke, Keysight, Brymen, Amprobe, Hioki, Yokogawa, and be sure you have a meter that actually is as "safe" as it claims. That is not to say that Flir, or others would be equally as good just that I don't have enough experience with them to say anything useful.The point of this thread is not to say that the meters listed are unsafe in any circumstance. The point is to point out the flaws. Safety is not just about the meter. The idiot holding the meter has more to do with safety than does the meter. But if you trust a meter to do what it says and it can't and the specs are a lie then you need to know so you can adjust your behavior to be safer.

author: ElektroHS
author_rank: Contributor
timestamp: March 16, 2021, 05:12:48 pm
content: Quote from: Lightages on December 05, 2020, 02:37:43 pmyou are right... any electrical device is "dangerous" in case of incorrect usage. Therefore "end-user" should follow all rules to be safe... otherwise the result of incorrect usage even certified meters can be ended not so good.

author: Andrew LB
author_rank: Contributor
timestamp: September 16, 2021, 05:38:41 am
content: Quote from: exit_failure on June 23, 2020, 10:12:54 amWhat you say is no longer the case. To have a meter UL listed it must adhere to the adopted IEC standards and include category overvoltage testing to ensure compliance. UL610101 and IEC610101The old standards found in IEC348 and UL1244 did not require cat compliance.

author: Rita
author_rank: Newbie
timestamp: October 08, 2021, 12:50:45 pm
content: Scanning through this thread there are repeated mentions of meters bearing the CE mark. Not all CE marks are the same.There's the The Conformité Européenne CE mark and the China Export mark. I'll leave you to decide which is a copy of which and why they look so similar.More info here:https://starfishmedical.com/blog/conformite-europeenne-mark-vs-a-china-export-mark/

author: ksio89
author_rank: Contributor
timestamp: October 08, 2021, 03:25:15 pm
content: I'm in the middle of an online course about safety (Electrical Measurement Safety Online Course), and now I understand why I should keep Chinese DMMs away from mains or larger voltage sources, why measurement equipment from reputable brands such as Fluke or Keysight cost what they cost and why professionals pay more for safer equipments. It shows a lot of pictures of toasted DMMs due to low quality fuses, fake CAT ratings or cheap test leads. They even show what happens to a dummy in a arc flash blast and a interview with a electrician who survived such incident, very scary stuff.According to the presentation by Fluke, around 15-20% of the cost of good electrical meters is composed by input protection, either manufacturing or testing, it's way more serious that I thought it to be. Guess I'll stick my Chinese DMM, which does not have a single certification mark, to use on low power electronics only.

author: VK5RC
author_rank: Unknown
timestamp: October 25, 2021, 06:47:25 am
content: I can't comment about meter safety but fully support issues with the user, even a well trained user having a bad day, distracted or in a rush can stuff up - I have, do and will again in the future, I appreciate other safety systems that I try NOT to rely upon - but appreciate their presence. One of the better comments I got from an experienced field technician - before you power stuff up, have a break then come back, look it over and re-check. Has been very helpful advice for me.

author: Brumby
author_rank: Unknown
timestamp: August 30, 2022, 02:32:39 am
content: Bump - just to demonstrate a point.

author: floobydust
author_rank: Super Contributor
timestamp: January 12, 2023, 08:55:21 pm
content: Wavetek Meterman HD110 (2nd generation Taiwan build) with huge LCD 21mm or 3/4", circa 2000.Trashbin find, I was repairing it and then saw this at the input jack boardSpacings are maybe 1mm at best, in many places. Basically terrible. Rated 1,000VAC 1,500Vpk, 3kV for 10usec and has no formal agency approvals.

author: siealex
author_rank: Regular Contributor
timestamp: August 09, 2023, 01:40:00 pm
content: DT832 from an unknown Chinese manufacturer.On the front panel I read: 200 mA MAX. On the PCB near the fuse: 0.5 A 250 V.Now the fuse itself. A miniature fuse (approx. as a germanium diode), but its filament looks WAY too thick. No marking at all.Several AA batteries, a 10 A meter, this fuse...2.5 A: no reaction at all.4 A: no reaction, only some heat.4.6 A: the filament starts glowing red, but does not melt. 30 seconds (I couldn't resist that heat any more) - no melting.The resistance of test leads did not allow me to push higher currents into the fuse.Then... FIVE!!! AA alkaline batteries in series (typically ~10..12 A short-circuit current), a piece of thick wire, no meters. The fuse tripped in TWO SECONDS!Is it a 5 or 6 A fuse? A slow-acting fuse typically melts in several seconds at 2x load. A 0.5 A fuse should melt in two seconds at 1 A, not 10 A.WHY??? Now it's unsurprising that the first thing burning in these meters is the PCB or resistors on it, then the ADC chip, the switch contacts, but not that damn fuse.