Testing Lightswitches with Multimeter

daggy

Some of you will have seen my other threads regarding installing lightswitches.

Anyway, after a quick chat with a sparky I decided to buy a cheap mutimeter from wilkinsons to replace the screwdriver tester.

Anway I bought this, or rather it's the same meter but rebranded and in a differen colour... same functionality from what I can tell.

heres a ic of the one I ended up with...

Anyway, I'm an electrical noob..I just want to use the multimeter to test that the switch is dead beforeI start taking wires out; can someone tell me how to do it?

I've read the instructions and tried google, but to no avail.

Ebe_Scrooge

Eerrrm - with respect, if you're not sure how to use it, I would say the safer option would be to simply switch off at the mains before you start fiddling about. Not meaning to be discourteous, but you really don't want to be chancing your arm with 240v if you don't really know what you're doing.

mchale

With respect make a note of this you may need it 999 :rotfl: :rotfl:

daggy

mchale wrote: »

With respect make a note of this you may need it 999 :rotfl: :rotfl:

I prefer 112

Ebe_Scrooge wrote: »

Eerrrm - with respect, if you're not sure how to use it, I would say the safer option would be to simply switch off at the mains before you start fiddling about. Not meaning to be discourteous, but you really don't want to be chancing your arm with 240v if you don't really know what you're doing.

Sorry, i didn't make my intentions clear

I was always going to turn off the lighting ciruit at the mains; I'm not trying to find out which wire does what... I just want to use the multimeter to verify that the circuit is isolated.

I've been doing some research and I use the AC V setting and the dial goes to 500v (closest one thats over 240), but where do I connect the to 'prongs'?

Red to the live and black to common?

Thanks guys

Meepster

If I was in your position and had NO previous experience of dealing with electrics, here is what I would do:

1) Take multimeter back to place where purchased from for a refund.
2) Call person who is fully compliant with Part P of the building regulations
3) Make brew and watch TV

Anything other that this is just asking for trouble...

maninthestreet

daggy wrote: »

I prefer 112



Sorry, i didn't make my intentions clear

I was always going to turn off the lighting ciruit at the mains; I'm not trying to find out which wire does what... I just want to use the multimeter to verify that the circuit is isolated.

I've been doing some research and I use the AC V setting and the dial goes to 500v (closest one thats over 240), but where do I connect the to 'prongs'?

Red to the live and black to common?

Thanks guys

Surely you can easily test if the power is off to the light in question by putting a bulb known to work into the light fitting, and then trying to switch the light on?

daggy

maninthestreet wrote: »

Surely you can easily test if the power is off to the light in question by putting a bulb known to work into the light fitting, and then trying to switch the light on?

Yep was going to do this too.. previously I'd done this and verified it using the screwdriver tester, but on the advice of a sparky I replaced the driver tester with a multimeter...

I just assumed it was good practice to test the circuit is dead with the multimeter instead

iamcornholio

You are better off buying one of those volt sticks which light up when power is present - test it on a known live circuit first and then the switch

Fifer

Sorry, it's probably not the advice you're looking for, but much as the others have been hinting, if you don't know how to use a multi-meter, you really shouldn't be working with mains electricity.

27col

You are over complicating the problem. But I don't think that I will give you any pointers as to what you are trying to do, for your own safety.
As someone has already said, if the mains are off at the consumer unit that should be all that is required.
Have the light that is controlled from the switch "on". When the correct mcb or the main switch is tripped then the light concerned will be "off". If the light is "off" then it follows that the switch is isolated.
Your question does not fill me with any confidence as to your ability, as far as electricity is concerned.

DVardysShadow

daggy wrote: »

Yep was going to do this too.. previously I'd done this and verified it using the screwdriver tester, but on the advice of a sparky I replaced the driver tester with a multimeter...

I just assumed it was good practice to test the circuit is dead with the multimeter instead

Apart from the fact that you don't know where to shove the multimeter probes, the big problem with testing devices is that if they show 0 Volts, you never know if it is because the circuit is dead or it is because you are not actually making contact with live conductors or [especially for a cheap multimeter] it is because the leads have fallen out or the multimeter is having a funny 5 minutes.

I prefer to switch something on connected to the circuit, and trip the circuit, then inspect to see that whatever I switched on is now off. Tripping a circuit does not always ensure full isolation from mains, depending on what you trip out, so the fool proof way is to switch it off at the mains.

But like the others, I don't think you know enough to work safely on mains electrical wiring. I suggest you rectify that gap in your knowledge to the point where you can sort out for yourself how to use a multimeter.