Cheap multimeter?

[Chuckles586]

Any recommendations for a cheap multimeter?

I need it to check the cables that lead to an old extractor fan in my loft which I want to remove.

Also, as I'm basically a novice, any tips on removing old cables safely would be very handy.

 

[ericmark]

Multi-meters are cheap, however the leads to use them on low voltage (50~1000 AC) are more expensive than the meter. gs38[/B].pdf]GS38 is what is normally quoted as the standard required.

One of the big problems with meters is leaving it on the wrong setting, this can result in ionisation of the atmosphere (big bang) so best option is to have a meter where the wrong setting will not result in this. I use a digital clamp on ammeter, which will also measure volts, ohms and frequency, but since there is no wired amp setting it is unlikely to cause ionisation.

 

[Taylortwocities]

Yes, GS38 leads are a requirement for your professional electrician, but not necessary for the basic tests that you have in mind, providing you are careful that you are on the correct setting and where you put your fingers!

Maplin have basic multimeters for under a tenner. Other shops are available.

any tips on removing old cables safely

Yes confirm that the cables are isolated*
Usually this means determining where they come from and disconnecting at the source.

*See the WIKI for safe isolation procedures.

 

[Nozzle]

Anything from a reputable hardware dealer such as Toolstation, Screwfix, Machine Mart, Maplin etc will do you. The key to it is knowing how to use one.

Nozzle

 

[JohnW2]

One of the big problems with meters is leaving it on the wrong setting, this can result in ionisation of the atmosphere (big bang) so best option is to have a meter where the wrong setting will not result in this.

That is a theoretical risk, if one is careless, but it's no more of a 'big problem' than leaving a manual car in gear when it's parked, switching off the power to a tool whilst it is running 'locked on' (in both cases assuming there is no interlock/NVR), putting salt in a dish when it should be sugar etc. etc. In all walks of life, one has to be careful.

I use a digital clamp on ammeter, which will also measure volts, ohms and frequency, but since there is no wired amp setting it is unlikely to cause ionisation.

I hope that doesn't give you false confidence - I'm not convinced that your meter would necessarily be too happy to be connected to, say, a couple of hundred volts or so when on a 'low ohms' setting! Worse, whilst many meters have fusing for high current ranges, they don't for resistance (unless one uses fused leads).

Kind Regards, John

 

[ericmark]

Yes leads to GS38 so fused, and yes maybe in ohms range some meters may overload. But it does reduce the chances.

 

[JohnW2]

Yes leads to GS38 so fused, and yes maybe in ohms range some meters may overload. But it does reduce the chances.

In fact, I doubt that fusing would make much difference on an ohms range, but 'a couple of hundred volts' might well kill the electronics of the meter (unless something has been built in to protect against such use!), quite probably leaving any fuse intact.

However, as I said, there surely must be an expectation that a reasonable degree of care will be exercised when using a meter (or anything else). Let's face it, a meter is only a type of 'tool', and the scope for causing damage/harm (even death) when misusing almost any type of tool without care is enormous - whether one is talking about an industrial lathe, a chisel or a kitchen knife!

Kind Regards, John

 

[John D v2.0]

Completely ot, but I always leave our car in gear when parked. Good back up to the hand brake!
Edit: presumably in case someone starts it without sitting in and it drives away, but I always hold the clutch to start it and my handbrake used to be useless so it would definitely roll away otherwise!

 

[DaveHerns]

Have a play with your multimeter on batteries etc before you use it for real on the mains

 

[Gerrydelasel]

I need it to check the cables that lead to an old extractor fan in my loft which I want to remove.

Sounds like you're just checking to see if they're live? Would an indicating screwdriver not do?

 

[Taylortwocities]

Would an indicating screwdriver not do?

No it will not "do"

Live conductors include the line and the neutral.

Will your magic wand tell you if the neutral is there, and properly connected??

No it will not. I any case, I would not rely on one of those for anything more than a very cursory check, to be confirmed by a proper test. Those things give very spurious results, and don't even get me started on "neon" screwdrivers…

 

[Gerrydelasel]

Will your magic wand tell you if the neutral is there, and properly connected?

I was under the impression he was removing the cables, so pretty soon it's not going to be connected at all?

 

[stillp]

no more of a 'big problem' than leaving a manual car in gear

A few years ago I had a company car that rolled away from outside younger daughter's house and demolished a garden wall at the end of the street. If it hadn't, it would have crossed a main road (bus route) and gone straight into someone's living room window. The handbrake had released itself. The car manufacturer pointed out that the driver's handbook said it should always be left in gear if parked on a hill.

 

[JohnW2]

A few years ago I had a company car that rolled away from outside younger daughter's house and demolished a garden wall at the end of the street. If it hadn't, it would have crossed a main road (bus route) and gone straight into someone's living room window. The handbrake had released itself. The car manufacturer pointed out that the driver's handbook said it should always be left in gear if parked on a hill.

Indeed, and it's a habit that persists with me, too. However, that doesn't alter what I said - that the hazard posed by leaving a meter switched to its current range is analogous to that posed by leaving a parked car in gear (even if deliberately). In either case, the user has to exercise caution when next using the item (meter or car) if they are to avoid the risk of 'the (possibly damaging or dangerous) unexpected'!

Although I'm as capable of oversights and errors as anyone else, I would like to think that I never usually apply the test leads of a multimeter to any circuit before first checking to see what range it is switched to .... and, moving to the analogy, I'm pretty sure that at the time I took my driving test (and quite probably still today), failing to check that the car was not in gear before starting the engine was very likely to result in a 'fail'.

... and, yes, one of those 'oversights' has resulted in my starting a car engine whilst it was in gear, although fortunately without any significant 'consequences'!

Kind Regards, John