| Products > Test Equipment |
| Big Clive's "Trashy" meter, unboxed ( Duratool D03047 multimeter ) |
| << < (36/43) > >> |
| switchabl:
--- Quote from: floobydust on April 27, 2023, 09:00:27 pm ---Cat. I 300V is a 1,500V impulse, Cat. I 600V 2,500V and there is no "500V" mains category. --- End quote --- That would be "overvoltage category I", not "measurement category I" which used to be defined in IEC 61010-1. The latter just means that the measured circuit is "not directly connected to mains". The necessary overvoltages ratings are supposed to be application-dependent and are supposed to be documented by the manufacturer. EDIT: "There are no standard transient levels defined for these circuits. An analysis of the WORKING VOLTAGES, loop impedances, TEMPORARY OVERVOLTAGES, and TRANSIENT OVERVOLTAGES in these circuits is necessary to determine the insulation requirements and short-circuit current requirements." |
| floobydust:
Duratool D03047 multimeter, suitable for mains measurements or not? :popcorn: |
| switchabl:
Well, assuming the CAT I label is not fake, so long as your mains is "not directly connected to mains", you should be fine. :horse: |
| Someone:
--- Quote from: joeqsmith on April 27, 2023, 01:53:22 pm --- --- Quote from: Someone on April 27, 2023, 01:23:16 am --- --- Quote from: joeqsmith on April 27, 2023, 12:39:49 am ---My home has a tiny little service coming into with a small distribution transformer. Nothing like the feeds for the buildings where I worked. Outlets at my house are several feet from the main feed and are behind small CBs which is behind another small one. Worse thing that will happen if I pull and outlet and short the wires, I blow a breaker. Hardly CAT III or risk of an arc flash. --- End quote --- So what's the supply impedance at those socket outlets? --- End quote --- I'll try and make a few measurements today with my tiny home wires. I assume you will do the same so we have something to compare. If not, I can measure some larger circuits. ... I assume because we are talking commercial vs industrial, you want to keep this below 250V? Are you wanting any other metrics or just the impedance for the three legs? --- End quote --- I'm out of that work these days so don't have the instrumentation to hand. It would be very interesting to see just how high impedance can get on your "wimpy" installation. (over here the target end to end is less than 5% droop so there is an upper ceiling). But as this keeps coming back to the same point, it will be possible to find all sorts of installations that will have prospective fault currents and robust voltage filtering/complex impedances that they could well be safely measured with a lower category meter. That is entirely expected since the standards have to cover worst case installations. The "argument" is back to front, if people want to claim the category ratings are excessively strict then it is on them to show every installation meets their new criteria, on the other side I only need to show/find a single example at the limits to demonstrate they are sensible (quickly shown by the current capacity of residential feeds and GPO circuits with their associated maximum droop). |
| Someone:
--- Quote from: floobydust on April 27, 2023, 09:50:10 pm ---Duratool D03047 multimeter, suitable for mains measurements or not? --- End quote --- If you plugged that into mains power in Australia and something went wrong, it would be on you since the meter is not rated for that. That's going to be the same in most "developed" countries. |
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