6 ms·

Yeah, you have to pay for the extra liability the company incurs by rating things for extreme usage. I draw an analogy with multimeters. I've got a cheapo mult

by gh02t 10y ago

Yeah, you have to pay for the extra liability the company incurs by rating things for extreme usage. I draw an analogy with multimeters. I've got a cheapo multimeter with a safety rating that (dubiously) claims it's perfectly fine to jam the leads in an outlet. Would I? Hell no, it'd probably explode. Meanwhile I have a much more trustworth Fluke meter that cost literally 100x more that doesn't really do anything more than the cheapo but I'm not putting my life at risk probing an outlet. You pay for that confidence, not only because there is a much larger engineering effort required to design and test a safe device, but also because you expect that they would be held accountable if their shit gets you killed. A legit safety rating is incurring a substantial liability.

StavrosK 10y ago
Lucky for you, I already jammed my cheapo multimeter into the leads of an outlet, and I'm fine. The multimeter did explode, and it turned out that I was measuring voltage- and had the lead going to the amp section of the meter, so it kept showing 0 after its fuse blew. I figured the socket was dead, good thing I didn't stick my fingers in there.
- TorKlingberg 10y ago
  I'm not sure you can connect a Fluke's amp meter to an outlet either without blowing it. Hopefully, just a fuse.
  - StavrosK 10y ago
    Yeah, I was being semi-facetious. Clearly it was my fault, and I don't know if the Fluke is that much different in terms of safety from cheapo multimeters. It certainly has other features and works better overall, but I don't see why you wouldn't try to measure high voltages with cheapo multimeters.
    - gh02t 10y ago
      There's a huge difference in terms of input protection, actually. Fusing and a bunch of other protection circuits are the first line of protection... most cheap meters will have a glass fuse and little else (some not even that https://www.youtube.com/watch?v=glzLlPO6CjY https://www.youtube.com/watch?v=glzLlPO6CjY), while a better meter will have MOVs, PTCs and many more lines of defense. Nicer meters (especially those rated for working on really high voltages that can cause a literal explosion) will have metal blast shielding around the inputs. There's also isolation- on cheap meters it's pretty common to see poorly laid out circuit boards that have input traces too close together. High voltages will arc right across and boom. The nice meter I have would probably blow a fuse if you connected it to the wall on the current setting, but it's a fast fuse so the rest of the meter would be fine. The fuses in really crappy meters are often quite slow though, so they will blow and cut the circuit but not before the meter gets fried. There are different levels of "crappy" though. A lot of the cheap meters you can get nowadays are safe enough to jam in the wall, I'm not saying "oh you've gotta spend $1000 on a multimeter or you're gonna die." But if you're gonna probe high voltage you'd better get something nice. I have a $5 meter that claims it'd be good at 1000 V, but that is obviously a lie and would be suicide.
      - StavrosK 10y ago
        Ah, I see, thank you. I mostly work with the hobbyist 3.3/5/12V, so I don't really need a fancy multimeter (the socket experiment was a one-off and I should have used one of those screwdrivers with the light instead).
      - throwaway7767 10y ago
        I think you're being much too paranoid about this. Most multimeters I've seen, cheapo or not, are rated to at least 1000V (sometimes 2-5kV). Now, as with all cheapo chinese electronics, you have to assume there is no safety margin on that so I wouldn't probe 1000V with such a meter. But 110 or 220V? Go for it. I'd be genuinely surprised if any common multimeter can't handle that (assuming it's operated properly, set on the right scale and such). A fluke meter rated for 2kV can measure 2kV, because you know they have a decent safety margin there.

by gh02t 10y ago

StavrosK 10y ago

Lucky for you, I already jammed my cheapo multimeter into the leads of an outlet, and I'm fine. The multimeter did explode, and it turned out that I was measuring voltage- and had the lead going to the amp section of the meter, so it kept showing 0 after its fuse blew. I figured the socket was dead, good thing I didn't stick my fingers in there.

TorKlingberg 10y ago
I'm not sure you can connect a Fluke's amp meter to an outlet either without blowing it. Hopefully, just a fuse.
- StavrosK 10y ago
  Yeah, I was being semi-facetious. Clearly it was my fault, and I don't know if the Fluke is that much different in terms of safety from cheapo multimeters. It certainly has other features and works better overall, but I don't see why you wouldn't try to measure high voltages with cheapo multimeters.
  - gh02t 10y ago
    There's a huge difference in terms of input protection, actually. Fusing and a bunch of other protection circuits are the first line of protection... most cheap meters will have a glass fuse and little else (some not even that https://www.youtube.com/watch?v=glzLlPO6CjY https://www.youtube.com/watch?v=glzLlPO6CjY), while a better meter will have MOVs, PTCs and many more lines of defense. Nicer meters (especially those rated for working on really high voltages that can cause a literal explosion) will have metal blast shielding around the inputs. There's also isolation- on cheap meters it's pretty common to see poorly laid out circuit boards that have input traces too close together. High voltages will arc right across and boom. The nice meter I have would probably blow a fuse if you connected it to the wall on the current setting, but it's a fast fuse so the rest of the meter would be fine. The fuses in really crappy meters are often quite slow though, so they will blow and cut the circuit but not before the meter gets fried. There are different levels of "crappy" though. A lot of the cheap meters you can get nowadays are safe enough to jam in the wall, I'm not saying "oh you've gotta spend $1000 on a multimeter or you're gonna die." But if you're gonna probe high voltage you'd better get something nice. I have a $5 meter that claims it'd be good at 1000 V, but that is obviously a lie and would be suicide.
    - StavrosK 10y ago
      Ah, I see, thank you. I mostly work with the hobbyist 3.3/5/12V, so I don't really need a fancy multimeter (the socket experiment was a one-off and I should have used one of those screwdrivers with the light instead).
    - throwaway7767 10y ago
      I think you're being much too paranoid about this. Most multimeters I've seen, cheapo or not, are rated to at least 1000V (sometimes 2-5kV). Now, as with all cheapo chinese electronics, you have to assume there is no safety margin on that so I wouldn't probe 1000V with such a meter. But 110 or 220V? Go for it. I'd be genuinely surprised if any common multimeter can't handle that (assuming it's operated properly, set on the right scale and such). A fluke meter rated for 2kV can measure 2kV, because you know they have a decent safety margin there.