Already posted by you here (and has since been answered). Please do not post the same question multiple times. It makes people waste time answering a question that may already be answered and splits discussions. It is bad enough having two threads about the same meter; please do not make it worse.
Not Fungus, but my $0.02.Under what conditions do you feel having a separate on/off switch makes a handheld multimeter less safe than one where the function is built into the rotary selector?I do not think it is a big deal. The meter should be safe regardless of the switch and leads configurations. So powering on a meter with the switch set to current should not be a safety issue. That this is almost certainly not the case with this particular meter is a different issue.
Of course it can blow an (expensive) fuse or trip a breaker, shutting down a mains circuit. But those are not safety issues (unless there was a pre-existing one like a locked door that cannot be opened without electricity). I do not think it is an amazing design in combination with the shared current jacks. But I remember bench meters that used ganged switches for function switch (so it would be persistent across power off). They had a separate power button. And some had a shared V/mA socket. Never had any problems with that.Do you feel the separate mechanical on/off switch is less safe than an electronic one?Since power on/off on a DMM will not usually affect safety and function selection or voltage at/current through the test leads, I do not think this matters at all. Meters that use soft switching for functions (e.g. any modern bench meter) will usually default to a high impedance (e.g. DCV) state on power on.
The convenient on/off switch means the selector can literally be in any position when junior connects the probes.
I figured Fungus brought it up and could explain his reasoning. I appreciate the input if others want to chime in on this as well.
Based on his initial postQuoteThe convenient on/off switch means the selector can literally be in any position when junior connects the probes.it seems this is concern but I can't come up with a case were it would increase your risk.
The temptation will always to be to simply power it off when you finish using it instead of returning the selector to a safe position.
eg. After measuring current, the selector will be in an amps range. If you simply switch it off and the next reading is a power supply (or heaven forbid, mains AC) then that's where the selector will be when you connect the probes.
A meter that always forces you to move the selector to a safe position after use is much better IMHO. Extra points if the ranges next to the "OFF" position are the high voltage ranges.
Of course such a meter can be operated safely, but ... Harbor Freight giving away DT830B class meters with on/off switches seems dangerous to me.
The same argument can be leveled at meters with separate input jacks for current. You have to be diligent about swapping the leads back after every use. If you forget and your next reading is a power supply, then, pop!
Personally, rather than adding more complexity with shutters and shared/unique current inputs, if it were mandated that all meters for CAT III and up could not have a shunt, I personally would be fine with it. I'm sure most would not agree with me.
I hate to bring up AN8008/ZT109 HV spacings here, but I took my AN8008 apart and it seems the rotary switch is the bottle neck?
Forget my grumblings about the fuses and poor PCB layout and fake 61010 claims.
The rotary switch PCB track spacing measures 1mm, and the wipers' spacing 0.60mm so I imagine that's the limit.
I can't recall if joeqsmith has done a robustness test on this model, I think I saw the AN8002 test.
Personally, rather than adding more complexity with shutters and shared/unique current inputs, if it were mandated that all meters for CAT III and up could not have a shunt, I personally would be fine with it. I'm sure most would not agree with me.
Those meters can have current clamps so where's the problem?
Harbor Freight could also give away meters that only do volts and continuity. I'm sure that's 99% of what they're used for anyway.
Exactly! When I actually have to work in the wild, the meter I use does not have HRC fuses, or a shunt.
I hate to bring up AN8008/ZT109 HV spacings here, but I took my AN8008 apart and it seems the rotary switch is the bottle neck?
Forget my grumblings about the fuses and poor PCB layout and fake 61010 claims.
The rotary switch PCB track spacing measures 1mm, and the wipers' spacing 0.60mm so I imagine that's the limit.
I can't recall if joeqsmith has done a robustness test on this model, I think I saw the AN8002 test.
Is anybody still imagining this is a 'safe' meter?
The AN8002 did better than a Fluke 87V in joe's tests, I imagine this one will be similar.
Exactly! When I actually have to work in the wild, the meter I use does not have HRC fuses, or a shunt.
The little 101?
I hate to bring up AN8008/ZT109 HV spacings here, but I took my AN8008 apart and it seems the rotary switch is the bottle neck?
Forget my grumblings about the fuses and poor PCB layout and fake 61010 claims.
The rotary switch PCB track spacing measures 1mm, and the wipers' spacing 0.60mm so I imagine that's the limit.
I can't recall if joeqsmith has done a robustness test on this model, I think I saw the AN8002 test.
Is anybody still imagining this is a 'safe' meter?
The AN8002 did better than a Fluke 87V in joe's tests, I imagine this one will be similar.
Safety does not require the meter survives. This is a meter that is cheap enough so that if you do put it across 240V in resistance mode and some tracks evaporate, you can get another one. AN8001 type meters cost just US$12 including postage. The AN8008 was about $25.
It has been said many, many times that this is not the meter you should be using for high voltage or high energy use. I think we all understand that. Not sure why we have to keep repeating it. We get it.
Even the best meter is only "safe" on the day it leaves the factory. If you pick up a major brand name meter that several people use, you do not know if a switch contact has broken and is floating around in the case, or if someone has shorted out a blow fuse with copper wire. It may have had a serious overvoltage incident and someone didn't report it.
If you are working with dangerous energies, it is dangerous. If anyone is risking their life on any manufacturer's CAT rating, they are definitely taking a gamble. If I have to take a gamble, Fluke is a way better gamble then ANENG, but it is better not gambling. If I did use the AN8008 with high voltage in a way where it cannot do any damage if it fails catastrophically, it is much safer then a CAT IV 600V Fluke that I am holding in my bare hands right in front of my face.
I think the AN8008 is a great little meter to use on the bench with low voltage/low power circuits. People are buying it because it can read much lower voltages and currents then most multimeters. Nothing that can be said about the safety issues is a concern for this kind of bench use. If anyone does not wish to use a meter like this for low voltages because they do not trust the CAT ratings, that is their choice.
From a practical point of view, I still don't see how even this cheapo meter can be a real potential murderer.
Worst case is that you blow the internals up. (Unless you work without any other safety precautions, which is wrong anyway)
From a practical point of view, I still don't see how even this cheapo meter can be a real potential murderer.
Worst case is that you blow the internals up. (Unless you work without any other safety precautions, which is wrong anyway)
Guess some people here have never been into a science & physics department/laboratory
So can we please stop the whole safety debate?
From a practical point of view, I still don't see how even this cheapo meter can be a real potential murderer.
Worst case is that you blow the internals up. (Unless you work without any other safety precautions, which is wrong anyway)If you are talking about something really dangerous like 1000V DC at 1000+ amps peak, basically you have entered a different world. If a cheap meter fails, it will probably not be able to contain the arc within the case, it may violently explode and fragment, or the internal arcing may not stop which basically means the meter will catch on fire. The ABS case will not need all that much encouragement to burn. A megawatt of electrical power is not something you ever want to see released in your hand or near your face.
Even 50V in a massive standby battery bank can be extremely scary. I have seen someone go to hospital with a first degree burn from a mistake he made working with a 4x12V 7AH battery pack. (Wearing a metal watch band while working near the batteries).
I wouldn't want to use a cheap meter in either of these cases. I would go for properly rated meter, and then still be extremely careful.
Guess again.So can we please stop the whole safety debate?Posting a message debating safety seems like a very good way to do that .
Guess some people here have never been into a science & physics department/laboratory
I for one have been in many such labs and also many ASTA certificated ones as well and have seen first hand the huge destructive power of electricity with the damage done to bullet proof glass and walls that have been subjected to the fragments of electrical equipment that has blown apart as a result of them being tested to destruction in safety checks.
It is perfectly possible to purchase all kinds of equipment designed to be used by a surgeon such as a scalpel for instance, but having one does not make you a surgeon...
True, but most of these cheapo meters will only be used in a CAT II 300V environment even by the reckless idiots.
(with maybe an occasional foray into CAT III 300V)
True, but most of these cheapo meters will only be used in a CAT II 300V environment even by the reckless idiots.
(with maybe an occasional foray into CAT III 300V)Agreed. Does that make lying about it acceptable, though?
Well, not sending ANENG dozens of orders would be a start . As would be not recommending any meter that so blatantly lies about its safety.