Did i destroyed my Fluke 179 by measuring resistance on 220V live wire - Page 1
Forum section: electronics / testgear

author: RiRaRi
author_rank: Regular Contributor
timestamp: August 10, 2023, 10:41:14 pm
content: Hello. Recently i was trying to troubleshoot steam/clothing iron station and by mistake i measured resistance of live wire of heater to body of boiler (for more time then one second). I thought that it wasnt plugged in at the time. Fluke 179 showed some unreal resistance and it is working now okay. But my question is can it get out of calibration that way?Note: it does not have fuse for resistance so i didnt change anything. I have one 5 year old 13 dollar DMM from which i compared results in order to determine its accuracy and for voltage it is almost the same but resistance is about 1 ohm difference. Difference can also be because of cheap meter non-accuracy.

author: BeBuLamar
author_rank: Super Contributor
timestamp: August 10, 2023, 10:46:58 pm
content: No it wouldn't hurt the meter.

author: Fungus
author_rank: Super Contributor
timestamp: August 10, 2023, 11:08:46 pm
content: They're designed not to be damaged by that sort of mistake.Quote from: RiRaRi on August 10, 2023, 10:41:14 pmYep.Quote from: RiRaRi on August 10, 2023, 10:41:14 pmSounds good to me.

author: RiRaRi
author_rank: Regular Contributor
timestamp: August 11, 2023, 10:48:30 am
content: Thanks. Hope it cant go out of calibration that way

author: TERRA Operative
author_rank: Super Contributor
timestamp: August 11, 2023, 12:33:07 pm
content: The Fluke can handle it, it's part of what you pay for when you buy Fluke.

author: Njk
author_rank: Frequent Contributor
timestamp: August 11, 2023, 04:10:23 pm
content: Just recalled the case when one guy from the other team bought a used luxury car. Soon he'd noticed that the battery is discharging faster than it should, to his assumption. He was young and well educated SW guy. A good guy, but those usually knows about everything and he asked me for multimeter to check the leakage current. I gave him my Fluke 189 and he'd managed to blew the fuse inside. No problem, but the fuse is of special type, it must be made of platinum and diamonds. It's quite expensive and it's not wise to blew it in such a stupid way. But again, no problem, I'd just charged the shareholders a bit more for the operational expense. But it was not good and to prevent this from happen again I bought him Uni-T UT61 multimeter (AFAIR) and showed how to make that measurement properly. That was not successful as very soon he blew the fuse again. Fortunately, that fuses are cheap and easy to find. Form that point, Uni-T is definitely better. Flukes are not for everyone.

author: slavoy
author_rank: Regular Contributor
timestamp: August 11, 2023, 05:10:16 pm
content: Quote from: TERRA Operative on August 11, 2023, 12:33:07 pmAs well as in any modern chinese autoranging multimeter

author: coromonadalix
author_rank: Super Contributor
timestamp: August 11, 2023, 05:46:25 pm
content: @slavoyi would not say that, if the design is not well doneauto-range as nothing to do with that, many parts could blow before the auto-range kicks in ...pls name your modern chineese stuff loll

author: RiRaRi
author_rank: Regular Contributor
timestamp: August 11, 2023, 08:51:49 pm
content: So even if you measure resistance with both probes on live wire 220V it can not hurt it?

author: floobydust
author_rank: Super Contributor
timestamp: August 11, 2023, 09:05:06 pm
content: For how long?

author: RiRaRi
author_rank: Regular Contributor
timestamp: August 11, 2023, 09:25:50 pm
content: About 15-20 seconds. Also beeper/continuity. I mean everything works but i dont know if i messed accuracy.

author: Fungus
author_rank: Super Contributor
timestamp: August 12, 2023, 06:17:04 am
content: Quote from: RiRaRi on August 11, 2023, 09:25:50 pmNo, you didn't.Relax.

author: BeBuLamar
author_rank: Super Contributor
timestamp: August 12, 2023, 11:06:05 am
content: Quote from: Njk on August 11, 2023, 04:10:23 pmI have done it enough time with the Fluke when I was in a hurry tried to measure voltage (120V to 480V) with the test leads plug into the current measurement jack. It blewd the fuse but I am glad that it blew the expensive fuse because the cheap fuse may explode.

author: Njk
author_rank: Frequent Contributor
timestamp: August 12, 2023, 10:06:24 pm
content: Quote from: BeBuLamar on August 12, 2023, 11:06:05 amNo argument, sometimes a blown fuse can be a huge bargain. But generally, electricity is not something that is intentionally trying to kill you. Human beings are more dangerous in that regard. Flukes are a nice toys, no doubt and sometimes they can be of very high value. Imagine you gave to someone a tool to do the work and the shit happened. I doubt the lawyers will consult with Charles Darwin about the root cause of the accident. They likely will demonstrate their professionalism trying to make you responsible. At that time, Fluke can protect you very effectively.But I'm not sure it's the best brand for casual use. Once I was preparing to long distance car trip and bought a couple of cheap rugged multimeters of random brand (see the image). One for myself and one for use at work by all, to check power supply voltages before connecting the boards. I was considering it an expendable thing, but it continues to work fine for many years, to my surprise. Never blown the fuse so not sure what will happen, but a lot of mechanical abuse, winter work outside, etc. Still works and I'm using it for occasional LV repairs and in car. It displays something that looks plausible and that's all I need. Anyway a serious work is done in the lab so I'm not sure a handheld device needs to be of high accuracy.BTW, based on the bright pictures at the Uni-T site, it seems I was wrong. It was UT71 multimeter, not UT61. The guy was very proud of himself and I was afraid of insulting him with a cheap gift. UT71 looks more professionally, it's something comparable to Fluke 189 so no one could say that mine is better so all were happy.

author: Fungus
author_rank: Super Contributor
timestamp: August 13, 2023, 05:47:30 am
content: Quote from: BeBuLamar on August 12, 2023, 11:06:05 ama) Always put the leads back to the voltage socket after measuring current. NEVER store it with the leads in the current jack, it's guaranteed way to blow a fuse.b) Get a meter with beep-alert on the current jacks. I personally wouldn't buy an expensive meter without that feature, but many Flukes don't have it.PS: I've deliberately plugged $13 meters into the mains on resistance mode and they survived.

author: slavoy
author_rank: Regular Contributor
timestamp: August 13, 2023, 08:21:27 am
content: Quote from: coromonadalix on August 11, 2023, 05:46:25 pmAuto-range is on the low side, 1000V protection is very common in many cheap multimeters like UNI-T, Habotest etc. for every input. I've checked a few myself.

author: Gyro
author_rank: Super Contributor
timestamp: August 13, 2023, 09:29:19 am
content: Quote from: slavoy on August 13, 2023, 08:21:27 amI'm not sure whether you are being serious or naive. I suggest you read...https://www.eevblog.com/forum/testgear/a-list-of-multimeters-that-do-not-appear-to-meet-their-claimed-safety-specs/

author: BeBuLamar
author_rank: Super Contributor
timestamp: August 13, 2023, 12:56:04 pm
content: Quote from: Fungus on August 13, 2023, 05:47:30 amWell I always did that with a Fluke 87v which does have the beep alert. I put it on current measurement mode to use as a jumper, put the meter down. Then in a hurry I pick it up trying ot measure the voltage. Sometimes it's just 24VDC but at times it's 120VAC, 240VAC or even 480VAC. It's because I work in a hectic environment. Never did that with any other meters I have.

author: slavoy
author_rank: Regular Contributor
timestamp: August 13, 2023, 03:59:36 pm
content: Quote from: Gyro on August 13, 2023, 09:29:19 amI'm not quite sure what this has to do with the topic.Quote from: coromonadalix on August 11, 2023, 05:46:25 pmHere are some. I can turn the knob all day and nothing will happen.

author: Gyro
author_rank: Super Contributor
timestamp: August 13, 2023, 04:44:47 pm
content: Quote from: slavoy on August 13, 2023, 03:59:36 pmThe OP was using the meter on mains, safety is relevant.QuoteYou should never turn the function dial on a meter while high voltage is applied. You specifically referenced autoranging, so there wouldn't be any reason to even be changing voltage range.