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| Traceless:
Thanks everyone for the feedback. @Gregg: I've seen wuite some of joeqsmiths reviews they are indeed awesome. The reason I'm asking my original question is that I'm currently looking at a meter that noone, including Joe has tested yet. The Brymen BM089 which according to its datasheet complies with: UL/IEC/EN61010-1 Ed. 3.0, IEC/EN61010-2-033 Ed. 1.0, CAN/CSA C22.2 No. 61010-1 Ed. 3.0, IEC/EN61010-2-032 Ed. 3.0 & IEC/EN61010-031 Ed. 1.1:Measurement Category III 1000V & Category IV 600V AC & DC. At the first glance it is a pretty nice meter from a reputable vendor. One of the special features this meter has is a 3-phase rotation measurement function, so basically you can hook it up to a three phase mains supply and measure the phase sequence (it shows a little R with a clockwise arrow around, if L1, L2, and L3 are connected to the corresponding inputs). If you look at the meter closely it also has a test-lead-based DC µA range which happens to be the function right next to the phase rotation measurement. Also because it is a clamp meter it seems to have no fuse. So what is going to happen if that thing is attached to a 3-phase mains supply and someone accidentally turns the knob one position to the left (DC µA)? At first glace that seemed like pretty horrible design safety-wise. If you look at the specs more closely though, they say that the DC µA range of that meter has a burden voltage of 3.5mV/µA aka. 3.5kV/A which is pretty high. Still DC µA will create a short across the mains and there is a lot of energy involved... So the question is basically does any of the aforementioned safety-standards imply that they actually tested the meter with all three leads connected to mains and put it in the µA range and it didn't blow up? |
| mqsaharan:
There is no mention of fuse in the user manual (http://www.brymen.com/images/ProductsList/BM080_List/BM080-manual.pdf) as well. They may be using a PTC instead of a fuse there. I think it is best to ask the manufacturer directly about the safety of the meter and the user in case of user error. Also, the manual states that the third terminal is for 3 phase rotation measurement only. So, ask them about that too how well it is protected against misuse. Brymen is very responsive as per a few members who have contacted them. I'm sure they'll explain better. Also, their design choice of using 2xAA for a chip with 2.5V low battery threshold (2.85V low battery for Cap and Hz), in my opinion, is a poor choice. There is a little mistake in the manual regarding 2 captive screws on the battery cover. The picture on the next page clearly shows that there will be only one. Anyway, not important. I particularly liked the high sensitivity mode for phase rotation measurement for motors. It is a unique feature. Edit: Oh, I forgot to mention that in my humble opinion, it is always best to use fused probes like Fluke FTP with industrial mains regardless what meter someone is using. |
| Kleinstein:
The BM080 is a clamp meter and thus has no classical shunts for the current measurement and thus no fuse for the current ranges. The voltage/resistance ranges are normally not protected by a classical fuse, but more like PTC (the transition to polymer fuses can be a bit fluent) and resistors as series elements. These are not meant to be changed and thus not mentioned. A clamp meter is usually safe in the current ranges, however they are normally limited to higher currents and most for AC only. P.s.: The DC-µA range may indeed use a PTC of similar element as fuse. So it would not hard clamp the voltage with diodes as most other meters do when measuring current, but respont with a high resistance. Chances are the burden resistance would go up (at least with a little delay) when overloading. |
| mqsaharan:
He is talking about uADC function, which is, as per manual, using input jacks for measurement. Thus the concern regarding the safety of the user and meter when there is no mention of fuse in its literature. |
| Traceless:
--- Quote from: mqsaharan on December 02, 2022, 09:52:01 am ---There is no mention of fuse in the user manual (http://www.brymen.com/images/ProductsList/BM080_List/BM080-manual.pdf) as well. They may be using a PTC instead of a fuse there. I think it is best to ask the manufacturer directly about the safety of the meter and the user in case of user error. Also, the manual states that the third terminal is for 3 phase rotation measurement only. So, ask them about that too how well it is protected against misuse. Brymen is very responsive as per a few members who have contacted them. I'm sure they'll explain better. --- End quote --- That sounds like a good idea I'll ask Brymen themselves - cant hurt. Then again I'm pretty sure they would never write back "Yeah, sorry we screwed up on this one, sorry", even if they did. So I'm still interested in additional less biased opinions on the forum. --- Quote from: mqsaharan on December 02, 2022, 09:52:01 am ---Also, their design choice of using 2xAA for a chip with 2.5V low battery threshold (2.85V low battery for Cap and Hz), in my opinion, is a poor choice. There is a little mistake in the manual regarding 2 captive screws on the battery cover. The picture on the next page clearly shows that there will be only one. Anyway, not important. --- End quote --- Yes that is not great but can probably be mitigated a bit by using 1.7V lithium-AAs. --- Quote from: mqsaharan on December 02, 2022, 09:52:01 am ---I particularly liked the high sensitivity mode for phase rotation measurement for motors. It is a unique feature. --- End quote --- This is indeed a cool feature but not the only nice trick that meter has up its sleeve. It also supports 1-lead-contact-phase detection and thus can replace a voltage-tester and enable you to find the phase even without access to a ground terminal. --- Quote from: mqsaharan on December 02, 2022, 09:52:01 am ---Edit: Oh, I forgot to mention that in my humble opinion, it is always best to use fused probes like Fluke FTP with industrial mains regardless what meter someone is using. --- End quote --- Fused probes would be nice, but I took a look at the Fluke FTPs and they cost almost twice as much as the Brymen including accessories :o. --- Quote from: Kleinstein on December 02, 2022, 10:08:46 am ---P.s.: The DC-µA range may indeed use a PTC of similar element as fuse. So it would not hard clamp the voltage with diodes as most other meters do when measuring current, but respont with a high resistance. Chances are the burden resistance would go up (at least with a little delay) when overloading. --- End quote --- The high burden voltage I mentioned above also points in that direction. Still my gut-feeling about this still is more along the lines of: "This could be safe-ish, maybe?" |
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