Multimeter confusion Safe isolation

[gazdkw82]

Was testing voltage for safe isolation on my multimeter today as I left my fluke t90 at home, however something strange happened.

I put the multimeter on voltage ac and then measured between earth then line, it sparked and tripped the RCD.

I can only think iv done something silly and wrong with the multimeter.

Below is how I have the multimeter set up. I'm not familiar with using multimeters so my basic knowledge maybe my downfall.


Any ideas?

 

[telectrix]

you have got the red lead in the amps (flash bang) socket. move it over to the V/ohms/Hz socket.

and you should not be using a mutimeter to check for safe isolation. go and stand on the naughty step.

and i've given you a "dumb" for your post.

 

[Bob Geldoff1234]

You need to have the red lead in the v/hz socket.By having it in the amps socket you put your multimeter in series with live and earth and because current flowed it tripped the rcd.

 

[gazdkw82]

I'm sorry telectrix :-( I was in situ and thought it was my only was to know if there was a voltage or not. It won't happen again

 

[Andy-1960]

Have a look at this document produced by the HSE, all equipment used for proving dead should be GS38 compliant. http://www.hse.gov.uk/pUbns/priced/gs38.pdf

 

[gazdkw82]

Looks like I have been a silly boy

 

[telectrix]

we all make mistakes, as the hedgehog said, climbing off the bog brush. all part of your learning curve, mate.

 

[Andy-1960]

Good job there was an RCD, otherwise bang and flash may have been considerably bigger!

 

[D00DY_T00DY]

Looks like I have been a silly boy

However a lesson to remember.
May sound like I'm on the high ground but it's something I would do and be dumbfounded on why it happened. Then again my multimeter has only been used a handful of time and have my t5-600 in my bag at all times.
Something I can keep in mind too.

 

[gazdkw82]

I do feel a little silly but like you say its a lesson learned

 

[Richard Burns]

Always be familiar with the equipment you use, even if you have to read the instructions!
Using a multi meter as an ammeter is trying to get the resistance of the meter as low as possible (gives a short circuit), using a multimeter as a volt meter you are trying to get the resistance as high as possible (gives an open circuit). As an ohmmeter it is using the battery power to test the circuit and is not expecting an external voltage.

 

[Bobster]

I use my mulitmeter to prove dead all the time. However I work with control systems etc, I'm not carrying two testers that I can achieve the same thing with.

This is why GS38 states that only approved voltage testers should be used. To stop people testing on the wrong setting.

You've likely blown an internal fuse in that meter, looks like a clone of a Fluke so hopefully it has one installed the same.

Quick way to test, rather than take it to bits. Have your red lead in V/Hz and set to ohms on the dial. Stick the red probe tip into the A socket on the meter, if you have continuity the fuse is ok!

 

[gazdkw82]

Well looks like the fuse is blown now then :-/

 

[Bobster]

Well looks like the fuse is blown now then :-/

Take the back cover off, I'm guessing as it's a clone of a fluke you will have 2 fuses. Find the one that has blown, they should have a part number on, usually a few pence for a replacements from RS components. Although you may have to buy a minimum of 5 say.

If that's the case, you will have spares, hopefully you will never need them. It's far better the fuse going than it killing the multimeter. Or you in fact.

 

[telectrix]

better a blown fuse than burnt fingers.