Spark from multimeter probe

[Ramekin]

I tried to measure the voltage present at a light switch using a mutlimeter. I had the thing correctly set for 240v AC but when the second probe made contact there was a spark.

Was I being a complete muppet in the way I was using it, or does it sound like the meter was rubbish?

 

[sm1thson]

so you had the meter set for VAC, but were the probes in the correct sockets on the meter? (if you have it in the one for mesureing high Amps then it is a direct short circuit as you put the meter in series for this). (i have made some assumptions about your meter, like that it has removable leads).

it may be worth readdressing the manual, or atleast tring to get it working with an AA (set to Vdc) battery before going near the mains again!?! (setting back to Vac).

when you say spark, was it small or big! -no noise or bang?

 

[Ramekin]

Yes, I believe the sockets were correct, but it certainly won't heart to look at the manual again. I've tried it on a DC battery subsequently to check a doorbell and it worked ok.

It wasn't a big bang, but since I wasn't expecting anything it was brown trousers time! It happened a while ago so my memory is hazy but it may have tripped the swtich on the consumer unit.

If everything was set up correctly (and that is an "if") would you expect to get any kind of spark?

 

[industryspark]

this is the problem with multimeters, wrong probe combination or setting and you can put yourself in a position of danger.

were the leads damaged or did you accidentally short the probes together? could be a faulty meter.


you'l probably be aware of GS 38 that gives recommendation for equipment used for live testing. if not give it a read because its essential stuff. its easy to forget sometimes that our testers are the only things between us and a potentially fatal shock/explosion

i personally have seen some really poor/ cheap multimeters for sale that i wouldnt touch, makes me wonder how hey can get away with selling to be honest.

for proving dead and proving voltage i always use a voltage indicator and proving unit- much safer.

 

[Ramekin]

The leads are OK and I'm pretty sure I didn't short the probes togther.

I think I'll take the tip and ditch the multimeter in favour of a voltage indicator and proving unit. To be honest, my trusty Volt Stick is good enough for most things I'll ever need to do.

Thanks

 

[Spark123]

Did you have one of the probes plugged into the current socket? This makes multimeters act as a dead short, not a good idea, a cheapo one will likely be less forgiving than a decent one. The decent ones (fluke etc) have high breaking capacity fuses in them for such an event as do the probes recommended by GN-38.
Volt stick - would you trust your life to one??

 

[Ramekin]

Pretty sure I had the probes plugged in right but will double check for next time.

Wouldn't trust a volt-stick to prove there wasn't any mains, but do use it to prove that there is!

 

[Spark123]

I've found volt-sticks a bit coarse for this too, especially where theres any other power about. Good for fixing fairy lights though.