Author Topic: EEVblog #1007 - Is a $25 Multimeter Any Good  (Read 103958 times)

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Online Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #250 on: July 20, 2017, 06:15:36 am »
I think it may also be true that they would not be using a multimeter either, at the very least they would be using a dedicated voltmeter in order to minimise the chances of a high energy inrush surge to the instrument?

Yes. As Dave says, if he were an electrician he'd buy a meter with no current measurement ranges.

(ie. no fuses inside the meter, none!)

 

Offline G7PSK

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #251 on: July 20, 2017, 07:38:13 am »
I think it may also be true that they would not be using a multimeter either, at the very least they would be using a dedicated voltmeter in order to minimise the chances of a high energy inrush surge to the instrument?

Yes. As Dave says, if he were an electrician he'd buy a meter with no current measurement ranges.

(ie. no fuses inside the meter, none!)
Is that not what I said? when testing high energy circuits they did not use a multimeter they used a specialist piece of equipment, It was not just a voltmeter it tested things like the earth resistance and current as well as trip time and current in breakers some of the functions simultaneously and pretty much with hands off and out of the way. The Fluke adverts give the impression that it is OK to use a multimeter in such conditions and maybe Fluke meters are CAT rated correctly but they still wont protect you when a mistake is made or a very large surge takes place. I have not gone throgh the Fluke catalogue but I would expect they or one of the subsidiaries manufactures such specialist equipment. If you think about the Fluke foto. it could well be safer for the man shown to be holding the meter in one hand.
 

Online Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #252 on: July 20, 2017, 08:45:03 am »
Is that not what I said?

I don't know. You didn't say what "high energy circuit" was being measured. How many volts, what's the line impedance?

There are plenty of "high energy circuits" that a handheld multimeter is suitable for. eg. Anything classed as CAT IV is "high energy" and CAT IV handheld multimeters are real things.

The Fluke adverts give the impression that it is OK to use a multimeter in such conditions

The Fluke adverts don't say anything about what the 'conditions' in that photo are but I'm sure Fluke lawyers have approved it for publication on their web site. It will therefore be correct usage of a Fluke multimeter.

The photo shows somebody measuring 230V using a CAT III 600V Fluke multimeter. It looks like a CAT IV environment but that isn't stated. Even if it is a CAT IV environment I believe a CAT III 600V meter can be derated to CAT IV 300V so it's acceptable use (let the experts correct me if I'm wrong here).

For reference, the CAT rating chart is this:

« Last Edit: July 20, 2017, 09:03:31 am by Fungus »
 

Offline Electro Detective

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #253 on: July 20, 2017, 09:16:24 am »
The Fluke 117 won't even read after about 660? volts anyway I think

You get 'OL' 


which really means 'LOL'  buy a post GSM pre MIC?   87V    ;D 
« Last Edit: July 20, 2017, 09:18:18 am by Electro Detective »
 

Online Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #254 on: July 20, 2017, 09:35:40 am »
The Fluke 117 won't even read after about 660? volts anyway I think

So?

You get 'OL' 

which really means 'LOL'  buy a post GSM pre MIC?   87V    ;D

Get some sleep. It looks like you need it.
 

Offline Electro Detective

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #255 on: July 20, 2017, 10:30:47 am »
The Fluke 117 won't even read after about 660? volts anyway I think

So?

You get 'OL' 

which really means 'LOL'  buy a post GSM pre MIC?   87V    ;D

Get some sleep. It looks like you need it.

Speak for yourself bub, you seem to be a permanent 24/7 fixture here playing bossy boots every chance you get 
and popcorn bait anyone you please without hindrance or criticism aka   >>>  :popcorn: :popcorn: :popcorn:

Do you own a 117 and or 87V ?

I do, and know their limitations

There's a reason the Fluke 117 exists, it fits a low voltage price point that suits electricians and users that don't need 87 features

Do some homework to understand why Fluke would design the 117 series so they won't read past 660v, and why an 87V does,
as well as many poorly made meters on the market that shouldn't, 
instead of advising others to "get some sleep "


Don't forget to click "Report to moderator"   and get some troll calling in,

before you eventually "get some sleep "   :clap:



« Last Edit: July 20, 2017, 11:01:16 am by Electro Detective »
 

Offline TheAmmoniacal

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #256 on: July 20, 2017, 11:08:32 am »
Great deal on the Chauvin Arnoux Metrix MTX 3281-BT I mentioned earlier, new in box at only £125 ! http://www.ebay.com/itm/263062827260

They only ship to the UK  :(
I collect [corporate] mugs.
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Online Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #257 on: July 20, 2017, 11:25:01 am »
There's a reason the Fluke 117 exists, it fits a low voltage price point that suits electricians and users that don't need 87 features

"CAT III 600V" meters exist because that's a working voltage suited to three-phase industrial power systems all around the world. It's a minimum requirement. It's nothing to do with electricians, price points or features.

You can also use CAT III 600V meters to work on 240V mains distribution panels.

PS: Fluke makes several CAT III 600V meters which are cheaper than the 117.

"which really means 'LOL' buy a post GSM pre MIC? 87V"

I have no idea what you're talking about but I don't see why a 600V limit is "LOL" worthy. It's a sensible design choice based on real-world needs (see above).

« Last Edit: July 20, 2017, 11:54:48 am by Fungus »
 

Online ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #258 on: July 20, 2017, 11:57:09 am »
which really means 'LOL'  buy a post GSM pre MIC?   87V    ;D

I may be a bit thick here, but would appreciate an explanation of LOL, GSM and MIC in this context.
 

Offline EEVblog

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #259 on: July 20, 2017, 11:58:01 am »
I've now had three Aliexpress companies that sell the AN8008 (or their own branded one) and wanting me to promote their store  ::)
 

Offline joeqsmith

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #260 on: July 20, 2017, 12:34:32 pm »
Tell you what: I'll up my bet to the price of a meter. If anybody thinks an AN8008 won't survive the grill igniter I'll get a meter shipped to joe and you can send me the purchase price via paypal if it lives.

I appreciate the gesture.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #261 on: July 20, 2017, 12:52:16 pm »
I've now had three Aliexpress companies that sell the AN8008 (or their own branded one) and wanting me to promote their store  ::)

You mean they want you to put a link to their store in the video?

What sort of $$$ were they offering?  >:D

If you're not going to take them up on the offer than maybe you could post the (anonymized) messages here for LOLs! (or make a blab)

« Last Edit: July 20, 2017, 01:14:29 pm by Fungus »
 

Online Specmaster

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #262 on: July 20, 2017, 04:26:34 pm »
Great deal on the Chauvin Arnoux Metrix MTX 3281-BT I mentioned earlier, new in box at only £125 ! http://www.ebay.com/itm/263062827260

They only ship to the UK  :(
Hmm I wonder why this is now a discontinued model, anything to do with it being a clam shell design with its inherent weak link, that ribbon cable at all????
Who let Murphy in?
 

Offline TheAmmoniacal

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #263 on: July 20, 2017, 04:37:10 pm »
Great deal on the Chauvin Arnoux Metrix MTX 3281-BT I mentioned earlier, new in box at only £125 ! http://www.ebay.com/itm/263062827260

They only ship to the UK  :(
Hmm I wonder why this is now a discontinued model, anything to do with it being a clam shell design with its inherent weak link, that ribbon cable at all????

Hard to say why they have discontinued that design, forward it to me so I can have a look  8) I'll pay.
« Last Edit: July 22, 2017, 06:58:17 pm by TheAmmoniacal »
I collect [corporate] mugs.
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Online Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #264 on: July 20, 2017, 04:52:02 pm »
Sorry to repeat, but... I was just about to delete that image of the young electrician from my disk when I accidentally zoomed in on it.

The full comedic value was revealed to me, I had to share.

Just look at the size of the copper bars leading out of that monster circuit breaker he's poking at with his little neon screwdriver. How many amps?? The mind boggles. Looks like it would take a whole team of electricians just to move that switch. :-DD



« Last Edit: July 20, 2017, 06:02:01 pm by Fungus »
 

Offline floobydust

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #265 on: July 20, 2017, 05:09:45 pm »
That's a ridiculous photo!

No employer would allow you to even open the door on an energized panel, let alone no PPE like eye protection, gloves.
Then there's the $1 electrical tester with no return wire? How does it glow? From the dumbness lol  :palm:
Photoshopped busbars?
 

Online Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #266 on: July 20, 2017, 05:25:58 pm »
That's a ridiculous photo!

No employer would allow you to even open the door on an energized panel, let alone no PPE like eye protection, gloves.
Then there's the $1 electrical tester with no return wire? How does it glow? From the dumbness lol  :palm:

It's the gift that keeps on giving: If you reverse-GIS it you find it's used on pages and pages of schools for electricians.

Another gem:   :-DD



Photoshopped busbars?

Nope, there's lots of different angles of him poking at different parts of the panel.

https://www.shutterstock.com/cs/image-photo/electrician-works-electric-meter-tester-fuse-359798642

At least he turns his baseball cap around when he's working.
« Last Edit: July 20, 2017, 05:51:29 pm by Fungus »
 

Offline amspire

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #267 on: July 20, 2017, 05:30:43 pm »
The tester screwdriver doesn't need a return wire. Your body is a capacitor of about 150pF. The current from the mains to your body capacitance is enough to light the neon lamp.  The thing that makes it safe is the $0.001 Chinese series resistor.  What could go wrong with that?
 
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Online Specmaster

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #268 on: July 20, 2017, 06:23:50 pm »
That's a ridiculous photo!

No employer would allow you to even open the door on an energized panel, let alone no PPE like eye protection, gloves.
Then there's the $1 electrical tester with no return wire? How does it glow? From the dumbness lol  :palm:

It's the gift that keeps on giving: If you reverse-GIS it you find it's used on pages and pages of schools for electricians.

Another gem:   :-DD



Photoshopped busbars?

Nope, there's lots of different angles of him poking at different parts of the panel.

https://www.shutterstock.com/cs/image-photo/electrician-works-electric-meter-tester-fuse-359798642

At least he turns his baseball cap around when he's working.
If he's standing on the regulation rubber floor mat then that neon should not be glowing surely??
Who let Murphy in?
 

Online Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #269 on: July 20, 2017, 06:47:01 pm »
If he's standing on the regulation rubber floor mat then that neon should not be glowing surely??

It's not about conductivity, it's about capacitance.
 

Online Specmaster

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #270 on: July 20, 2017, 07:03:16 pm »
If he's standing on the regulation rubber floor mat then that neon should not be glowing surely??

It's not about conductivity, it's about capacitance.
There has to be a return path somewhere for the albeit, small current, for the neon to glow.
Who let Murphy in?
 

Offline deflicted

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #271 on: July 20, 2017, 07:11:44 pm »
My 4 year old son has a head-lamp exactly like the one in that photo. It's absolute junk, every bit as flimsy and cheap as you'd imagine, not even fit to be a child's toy. Plus the illumination it provides, even with fresh batteries, is terrible. If you used that to light up an electrical panel in a dark place, you'd barely be able to tell the black wires from the red wires. If that.

They might as well have shown him wearing one of these:

« Last Edit: July 20, 2017, 07:18:45 pm by deflicted »
 
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Online ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #272 on: July 20, 2017, 07:18:34 pm »
There has to be a return path somewhere for the albeit, small current, for the neon to glow.

Yes, but the return path can be via capacitive coupling to ground, rather than resistive.
 

Offline deflicted

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #273 on: July 20, 2017, 07:25:15 pm »
That's a ridiculous photo!

No employer would allow you to even open the door on an energized panel, let alone no PPE like eye protection, gloves.
Then there's the $1 electrical tester with no return wire? How does it glow? From the dumbness lol  :palm:
Photoshopped busbars?

Just out of curiosity, how would someone troubleshoot a panel like that if they're not allowed to open the door with it energized? Do they just have to dismantle the whole thing and bench test each component separately? Or maybe turn it off, hook up test gear, instrumentation, etc, then turn it back on and monitor from a distance?
 

Offline floobydust

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #274 on: July 20, 2017, 08:22:48 pm »
This panel has plenty of non touch-safe components, kinda home-made looking from 19" rack stuff

Qualified personnel (electrician+PPE) could make measurements on a live panel, but dangerous depending on the voltage class. It's frowned upon because always an idiot nearby and love that door swinging into you.
Electrician has 4kV motor control panel open, his equipment cart rolls and bumps into it and massive arc-flash explosion. Quite spectacular.
Properly, there is a lock-out procedure where you get a plant/site permit and pad-lock the disconnect off.


I don't think body-capacitance is enough for a neon-lamp that bright, 600VAC 60Hz 100pF I get Xc=26MEG and 19uA.
 


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