Electronics > Projects, Designs, and Technical Stuff
DMM Lead Arc getting voltage from power strip
wizard69:
If the meter has a resistance capability I'd most certainly test the meter for proper operation on the resistance ranges. This highlights the value of having a set of precision resistors or at least resistors that you have measure to a high degree of precision, in your possession. They don't have to be of "calibration standard" quality but they should be well known as to their acutal values. The nice thing here is that there are all sort of examples right here in these forums of how to create quick check standards. I call them quick checks because the intention isn't to be good enough to calibrate in many cases but good enough to prove operation of the tool.
If the meter still works I have a hard time believing that the meter caused your problem. It could be something you did or another factor.
By the way while this might rub many the wrong way meter leads are expendable wear items in my mind. Be prepared to buy new ones any time the current ones are damaged, show contamination or have been stressed excessively. I work in automation, with high voltage AC and DC systems, and frankly this is an area where you get no second chances. I hate to even think about how much current could be discharged from some of the motor drive caps I have to deal with. These are likely small caps compared to some stuff people work on but they make me pucker every time I work on them.
DW1961:
--- Quote from: wizard69 on July 29, 2020, 02:03:57 am ---
If the meter still works I have a hard time believing that the meter caused your problem. It could be something you did or another factor.
--- End quote ---
Wizard. It was as bad power strip that allowed the leads to cross the neutral and positive.
Gyro:
--- Quote from: DW1961 on July 28, 2020, 08:54:19 pm ---Is there anything can report from tearing it down that is either good or bad? I'll review it and add you analysis, if that's ok? Is it dangerous? Lacking in a way that is short lived? Anything you can think of.
--- End quote ---
As I mentioned, the level of protection is what you would expect in that price range. If it was a Fluke or something then you might expect VDRs, maybe even spark gaps - but that stuff comes with higher CAT ratings and you didn't pay for an expensive fluke, so you wouldn't expect them. At the same time, for general indoor mains use (wall sockets) and low voltages it should be fine (pushing the probes through mains strip internal metal parts permitting :)). Don't go probing around the inlet side of your breaker panel or substations and you ought to be fine. If you're going to do that, then buy a Fluke and some anti-flash gear.
You can't pull it up for lack of fuses because you wouldn't expect fuses without current ranges on the jacks - and the fuse advice was from some anonymous Amazon user anyway, so far as you can prove.
Check its voltage, resistance accuracy against another meter and if you're happy with it and its operation, then there's really nothing to fault for the price. I can't see anything obvious in the construction.
DW1961:
--- Quote from: Gyro on July 29, 2020, 08:43:37 am ---
--- Quote from: DW1961 on July 28, 2020, 08:54:19 pm ---Is there anything can report from tearing it down that is either good or bad? I'll review it and add you analysis, if that's ok? Is it dangerous? Lacking in a way that is short lived? Anything you can think of.
--- End quote ---
As I mentioned, the level of protection is what you would expect in that price range. If it was a Fluke or something then you might expect VDRs, maybe even spark gaps - but that stuff comes with higher CAT ratings and you didn't pay for an expensive fluke, so you wouldn't expect them. At the same time, for general indoor mains use (wall sockets) and low voltages it should be fine (pushing the probes through mains strip internal metal parts permitting :)). Don't go probing around the inlet side of your breaker panel or substations and you ought to be fine. If you're going to do that, then buy a Fluke and some anti-flash gear.
You can't pull it up for lack of fuses because you wouldn't expect fuses without current ranges on the jacks - and the fuse advice was from some anonymous Amazon user anyway, so far as you can prove.
Check its voltage, resistance accuracy against another meter and if you're happy with it and its operation, then there's really nothing to fault for the price. I can't see anything obvious in the construction.
--- End quote ---
Thanks. I gave it a good review and mentioned it's limitation, such as no DC current measurement.
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