Timeline for Does the maximum voltage on a multimeter refer to the maximum difference between the two points or the difference between the points and ground?
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
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| Sep 20, 2021 at 15:24 | comment | added | Spehro 'speff' Pefhany | At >10kV wrt earth the multimeter will not only be dangerous to touch but dangerous to get anywhere close to. The meter would also have to be insulated from ground because the case will not necessarily be designed for that level of insulation, and an arc to ground would destroy the meter most likely (or could kill some person that happens to form part of the current path). | |
| Sep 20, 2021 at 12:06 | answer | added | tobalt | timeline score: 1 | |
| Sep 20, 2021 at 11:37 | history | edited | Null♦ | CC BY-SA 4.0 |
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| Sep 20, 2021 at 7:33 | review | Close votes | |||
| Sep 20, 2021 at 11:37 | |||||
| Sep 19, 2021 at 19:15 | comment | added | Alix | @qrk, I've looked over my project and am going to try to switch things around to measure on the ground side as you suggest (it's more practical physically too, so that's convenient). Bimpelrkkie, thank you for your concern, though I should clarify that I am entirely aware that I'm in over my head and that I'm undertaking this project with oversight from people who know far more than I do. Eventually, my plan is to have an entirely separate display system managed with a raspberry pi so that there is absolutely no risk where measurement is concerned. | |
| Sep 19, 2021 at 18:57 | comment | added | Bimpelrekkie | Also consider using a wireless solution where the measurement part of the meter is separated from its display, for example: fluke.com/en/product/electrical-testing/digital-multimeters/… as long as you connect the meter with the high voltage off, this should be safe enough. Similar solutions exist using Bluetooth or Wifi. | |
| Sep 19, 2021 at 18:48 | comment | added | jonk | @Alix I'd recommend using an opto-isolator and a relaxation oscillator to measure the voltage across the current-measuring resistor and turn it into pulses of light that you can safely handle over a fiber link to where ever you and the pulse rate measuring device will be located. What dynamic range and precision do you require? | |
| Sep 19, 2021 at 18:44 | comment | added | John D | Find or hire someone who is qualified and competent to work with high voltages. It's not worth risking your life if you don't know exactly how to do it. | |
| Sep 19, 2021 at 18:42 | comment | added | qrk | What you are trying to do is outside the scope of the meter's intended use. Can you measure the current on the ground side? This is much safer. If you use the meter to measure current on the high side, you need to isolate the meter sufficiently so you don't get an arc from inside the meter to surrounding objects, including you (i.e., don't touch the meter). | |
| Sep 19, 2021 at 18:40 | comment | added | Alix | Thank you for your quick replies! Your response matches my understanding of what would happen (including the danger of the multimeter itself becoming dangerously charged). Is there a different technique for current measurement that would not entail such risk, besides having the measurement device placed far away from the display (as I plan to do anyway)? | |
| Sep 19, 2021 at 18:34 | comment | added | Bimpelrekkie | The ratings on the multimeter are for voltages between its connections, that doesn't mean you can safely measure any voltage, do you think it would be safe to use it to measure 10 V (much less than what the meter can handle) at a device that is at 1 MV (Mega Volt) above earth/ground while you're standing on earth, holding that multimeter? Across what will that 1 MV be? Hint: you will not survive this. | |
| Sep 19, 2021 at 18:30 | comment | added | Bimpelrekkie | Think about this: if the multimeter does not have ANY connection to earth/ground, how can is "see" that voltage? Also: it worries me in ways that you cannot imagine that you're working on something with 10 kV DC yet you have to ask this question. Perhaps you should educate yourself more before working with high voltages? | |
| S Sep 19, 2021 at 18:25 | review | First questions | |||
| Sep 19, 2021 at 20:10 | |||||
| S Sep 19, 2021 at 18:25 | history | asked | Alix | CC BY-SA 4.0 |