Oops! I think I want a new multimeter.

[smbaker]

I have a couple nice multimeters upstairs in my "lab" for electronics use, including a Fluke 87-V, but I usually keep a multimeter downstairs in the garage for automotive and household use. In this case it was a free circuitspecialists multimeter that I've had for a decade or two.

While wiring a 240VAC 30-amp RV receptacle, I figured I'd do a quick voltage check and grabbed the multimeter from the toolbox. There was a loud pop, the 30 amp breaker tripped, a small amount of brass from the receptacle was now welded to the multimeter probe, and something was rattling around inside the multimeter. It seems in my haste I forgot to check where the leads were connected, and whomever had used the multimeter last (probably me) has left the leads attached to the 500ma current jack.

Attached is a picture what the inside of the multimeter looks like. The stuff rattling around inside was fragments of the 500ma fuse. There's surprisingly little mechanical damage to the inside, just some deformation of the fuse holder and a lot of soot. It could have been much worse.

I've decided that using the cheapest sketchiest "free" multimeter that I own for the occasional mains work because it's too much work to trek upstairs for the good meter is probably not a wise idea.

I'm thinking of ordering a Fluke 117 to keep downstairs in the garage. Any thoughts on this meter? I've watched Dave's video and I realize that it's not suitable for fine electronic work (I have an 87-V for that), but it seems like a decent meter for occasional mains or automotive use.

[mzacharias]

I inadvertently connected my my Circuitmate (Japanese Beckman import) to 120v AC while on milliamp range. The 5x20mm glass fuse popped but that was it.

Boy did I feel:

a) LUCKY.
b) STUPID.

I know better after all these years but I just got "casual" and didn't double check first.

[ataradov]

For daily use I personally prefer UNI-T UT136B. They are decent meters and are very cheap. I especially appreciate the size, it is basically the same as all those Mastechs and numerous clones.

[smbaker]

I inadvertently connected my my Circuitmate (Japanese Beckman import) to 120v AC while on milliamp range. The 5x20mm glass fuse popped but that was it.

I just finished cleaning up the soot and doing a postmortem on the meter. What looked like a trace between the fuse and the 500ma jack is actually now the absence of a trace. It seems to have rather neatly vaporized the entire trace. There's also another trace between the two diodes next to the ground jack that also vaporized.

Needless to say, the 500ma range doesn't work anymore.

The DC 10 A range and DC V ranges are not reading what they should read.

[shteii01]

Fluke 27FM
When you need a tank that will survive WW 3, accept no substitute!
http://www.ebay.com/itm/Fluke-Multimeter-27-FM-Digital-includes-Probe-and-Operations-Manual-/331869654521?hash=item4d44f90df9:g:6cgAAOSwNsdXTe2Z

The 27FM has extra chip that will do RMS on the sinusoidal signals.

[ralphrmartin]

Isn't a voltage tester / continuity tester a better idea for this kind of job? E.g. UNI-T UT15C.

[MarkF]

I have both the Fluke 117 and the 87-V. I like both of them and only bought the 87-V for the low amp ranges. No issues with either.

If you buy from tequipment, don't forget the eevblog discount.

[poida_pie]

if I was looking for a DMM to leave in the workshop, I would look at the Fluke 17B and similar. Joe Smith has proven these are safe and hard to destroy.

My workshop DMM right now is a Fluke 27F/M, bought on ebay.
The 27 draws a tiny current from the battery and so lasts for years. It also is robust enough to take whatever idiotic things I can throw at it.

[joeqsmith]

Glad you are alright.  Meters are easily replaced.   

"a small amount of brass from the receptacle was now welded to the multimeter probe, "

Can we get a picture of what is left of the fuse and probes?  Did the probes open up?

[retrolefty]

 Measuring voltages while the probe is in the amp jack is the most common usage fault I seen. It's simply human error and nearly all of us pro or hobbyist has done this at one time or another. Generally once is enough to teach a lesson that sticks. Some meters can detect that the test lead is inserted in amps/milliamps jack but range is in volts and emit a warning tone.

[joeqsmith]

That's a good point.  Some like the Fluke 101 have no current measurement and so you would be hard pressed to make a mistake.  Not to mention that we still have no idea what it takes to damage a 101.  One day perhaps...

[saturation]

As a US buyer you have many choices.  Its rare to measure current in-series in field use for safety reasons so in practical use most technicians will use a good clamp meter.  The 117 is a good DMM. A drawback of the Chinese 100 series and the 101, is that they are averaging AC, but its main plus is its electrically tough.  Many field sources of AC often use cheaper modified sine wave inverters, which averaging AC DMMs cannot read well.  TRMS should be a norm all around.

[jeroen79]

Attached is a picture what the inside of the multimeter looks like. The stuff rattling around inside was fragments of the 500ma fuse. There's surprisingly little mechanical damage to the inside, just some deformation of the fuse holder and a lot of soot. It could have been much worse.

I have to ask, does the meter still work?

[bills]

Here is a good replacement for a volt/current tester.

http://www.tequipment.net/FlukeT5-600VoltageTester.html?Source=googleshopping&gclid=CjwKEAiA48fDBRDJ24_imejhwUkSJAAr0M5k0TMoUceByK_-5GltT-1laYpBlbLYdbbXkvEX_U8NMhoC6iPw_wcB

[shteii01]

If you want to save a couple of bucks: http://flukeonlinestore.com/products/factory-reconditioned/t5-600-usa-electrical-tester

Here is a good replacement for a volt/current tester.

http://www.tequipment.net/FlukeT5-600VoltageTester.html?Source=googleshopping&gclid=CjwKEAiA48fDBRDJ24_imejhwUkSJAAr0M5k0TMoUceByK_-5GltT-1laYpBlbLYdbbXkvEX_U8NMhoC6iPw_wcB

[smbaker]

"a small amount of brass from the receptacle was now welded to the multimeter probe, "

Can we get a picture of what is left of the fuse and probes?  Did the probes open up?

I probably made it sound more exciting than it really was, there's just a bit of brass plating on the tip. Probes are still usable. Picture of the probe under the microscope is attached.

The glass fuse was in pieces, and I'm afraid I've thrown the fragments away.

I have to ask, does the meter still work?

Yes, but its accuracy is greatly impaired. It's possible that it's fixable, if all that's wrong is the two traces that were vaporized from the PCB.

[joeqsmith]

"a small amount of brass from the receptacle was now welded to the multimeter probe, "

Can we get a picture of what is left of the fuse and probes?  Did the probes open up?

I probably made it sound more exciting than it really was, there's just a bit of brass plating on the tip. Probes are still usable. Picture of the probe under the microscope is attached.

The glass fuse was in pieces, and I'm afraid I've thrown the fragments away.

I have to ask, does the meter still work?

Yes, but its accuracy is greatly impaired. It's possible that it's fixable, if all that's wrong is the two traces that were vaporized from the PCB.

It was a glass fuse.  I missed that.  Those can be pretty exciting.   

[jonovid]

gos the old saying, their are good electricians and dead electricians. but never bad ones!  

[6581]

I probably made it sound more exciting than it really was, there's just a bit of brass plating on the tip.

Nah, having done something similar, accidental sudden explosive multimeter events tend to be quite 'exciting' - often requiring replacement fuse/meter/underpants. Happy to hear you weren't injured.

I can't give opinion on any other Fluke than 87V and you already know how great that one is. For a toolbox-DMM I'd probably value 1) safety, 2) battery life (and type), 3) compact size. Naturally it has to have ranges/features necessary for your work. Personally I'd probably consider EEVBlog Brymen although I don't like triple-A's.

[mos6502]

Fluke 101 + a nice AC/DC current clamp. Since the 101 has no current input, there's no chance of messing up.

Current clamps are definitely the way to go. Safer, easier, no voltage drop ...

[JonM]

One of my EEVBlog BM235 probes has a burn mark on it. A few months ago I had a problem with a wall light switch and stupidly failed to use one of the very nice insulating sleeves supplied with the meter. Using an (insulated) alligator clip on one probe I touched the other to one of the terminal screws to check for AC voltage. Somehow I rotated the probe while flipping the wall switch and hit the grounded switch frame. There were sparks, and the switch contacts were "cleaned" by the event causing the ceiling light to come on.

Of course I replaced the switch and tore the old one apart to see what the contacts looked like (very pitted). Soon after another switch on the same wall failed and I tore it apart as well. Those contacts were at least "dirty". Both switches had the remains of several very small insects, or maybe dust mites, that might have had something to do with the contact failures.

Bottom line for the theme of this thread: use probes with the minimal amount of conductor tip exposed!

Also +1 on clamp-on current probes, but they are not always easy to clamp on in confined spaces. Long ago I had a HP clamp-on DC current probe that was a lot smaller than the version I now have.

Jon