I can't recall the model, though it might have been the Fluke 287 or 289. Maybe the model was taken off the market because it was so lousy.
I can't recall the model, though it might have been the Fluke 287 or 289. Maybe the model was taken off the market because it was so lousy.Sorry for being OT, but for the record, a Fluke 287/289 definitely has a boot-up delay, but the continuity tester is specified at <1ms response time. The 289 I have here clocks in at around 500 usec. Subjectively, and relative to modern DMM choices, this is "very fast". Perhaps your colleague's unit was faulty.
So, with this thing built to Fluke levels of refinement you'd only pay $300? I'm sorry to say you are still very far off the mark.You got it backwards. What I meant is that with the UT71E built the way it is, I would not be willing to pay more than maybe half its current street price.
Most of the safety issues come from basic layout and mechanical design flaws that cost almost $0 to fix... or simply remove the CAT-III/IV rating claims - nobody will complain that a CAT-II multimeter is built like a CAT-II multimeter.
My bad. So you are saying that you value this meter at $60 but if they fixed if they fixed the issues that cost "almost $0 to fix" you would happily pay $180?
You have no idea whether it meets its safety rating or not. Even the version with glass fuses is allowed in some countries, where the latest IEC regulations are not enforced yet, like the USA.
Just because it has no MOVs or beefy current limiting resistors, doesn't mean it won't pass the IEC61010 test.
What i am having trouble understanding is how people are willing to accept that the chinese UT61 series for $60 is a good deal but the UT71 series for $130 isn't. Both promise cat IV and fail to deliver.Mt UT-61C bought from Reichelt in Germany is silk screened "CATIII 300V" and "CATII 600V". It also displays silk screened TÜVRheinland and GS logos. The TÜV logo for some reason says ID:0000000002, though.
im curious, what does it mean TUV ID 0000000002 ? a very old certification? outdated?
I'm pretty sure a 250V fuse, glass or otherwise, in a CAT-IV instrument that claims ratings above 250V does not meet CAT-IV even by the oldest relevant IEC standards. Same with the clearances that are nowhere near current specs, so likely many revisions out of date at best.
As for the missing MOVs, it is not just about safety but also about preventing the meter from getting ruined at the first minor surge or incident involving moderate voltages. Having a multimeter that won't kill you due to a minor electrical fault or user error is nice. Having a meter that will also survive said mistakes and faults with a blown fuse at worst is better.
As an average citizen, I would only test connections and appliances positioned in a CAT II environment. Anything above that rating, I'd call an electrician.
When using the Tester, if tip does not glow, voltage could still be present.
The Tester indicates active voltage in the presence of electrostatic fields of
sufficient strength generated from the source (MAINS) voltage. If the field
strength is low, the Tester may not provide indication of live voltages.
As an average citizen, I would only test connections and appliances positioned in a CAT II environment. Anything above that rating, I'd call an electrician.
Or just get one of these:
Even the Fluke branded ones are only about $20. If you're regularly sticking bits of metal into household electrical sockets to see if they're live or not then you're doing it wrong.
I'm pretty sure a 250V fuse, glass or otherwise, in a CAT-IV instrument that claims ratings above 250V does not meet CAT-IV even by the oldest relevant IEC standards. Same with the clearances that are nowhere near current specs, so likely many revisions out of date at best.
As for the missing MOVs, it is not just about safety but also about preventing the meter from getting ruined at the first minor surge or incident involving moderate voltages. Having a multimeter that won't kill you due to a minor electrical fault or user error is nice. Having a meter that will also survive said mistakes and faults with a blown fuse at worst is better.250V glass fuses are allowed under the previous regulations, even under CAT IV 600V. The test only required a maximum of 1000V on the amp range for 1 minute, with blown fuses in place to check for arcing. There was no requirement for 1000V HRC fuses.
Did you measure the clearances and creepage distances? Do you know where to measure them? The trace Dave pointed to, is not a high voltage one and may not matter.
If you can tell a meter doesn't meet its specs at a glance, perhaps you should work for a UL lab and save them a load of cash in unnecessary testing.
The meter is already protected up to 1000V by crowbar transistors.
The PTC will do its job of clamping the voltage above that when required.
The MOV is not a requirement, but an additional protection, to back up the PTC.
If you suspect your meter was hit by high voltage transients, MOVs and PTCs should be replaced, as they degrade quite a bit after each activation. Even if your meter survived.
You are also wrong with the Chinese multimeter manufacturers. C.E.M and others have been sending their meters for independent testing for years. UNI-T is now doing the same. Brymen also manages to submit to independent testing, while keeping their prices reasonably low.
The PTC will do its job of clamping the voltage above that when required.
The MOV is not a requirement, but an additional protection, to back up the PTC.
There is no scenario where you will get high voltage transients on the current ranges.
...
If you measure current in series within a mains circuit, with high voltage transients present, the voltage will be low across the meter and the fuse will rupture if the current goes high for long enough (doubtful with short transients).