Voltage Tester Recommendations

[aesmith]

By the way, the "big bang" and "little fuse" points sound contradictory. Surely you can only make a little bang when blowing a 300mA fuse? To do that I'd need to have the meter set to either AC or DC current, and have the +ve lead in a different socket. I'm not going to try that to see how big a bang it makes.

An improper fuse on a circuit with a very high rated breaker or fuse (ie. before your MCBs) may fail to interrupt the current. This would have fatal effects on the multimeter, and rather bad ones on your hand. There are also other concerns with very high energy circuits (an inappropriate and inappropriately used multimeter caused an arc between unprotected phases, resulting in the death of the operator and significant damage to the building, in one notable incident).

Was that on 240V? In a system with say 300mA fuse in the meter, 32A MCB on the circuit, and 100A supplier fuse, surely it's going to be the 300mA fuse that blows. Aren't the upstream breaker/fuse ratings irrelevant at that point? Otherwise what's the point of correctly fusing a piece of equipment?

 

[aesmith]

Are you wanting a meter that gives a measured voltage, or one that indicates that a voltage is present?

For the purposes of this question, just testing for presence or absence of mains voltage. For example when installing or troubleshooting the heating controls, or checking that I've isolated the correct circuit before working on it.

 

[PrenticeBoyofDerry]

I have both a martindale with prover http://martindale-electric.co.uk/martindale-vi137002-voltage-indicator-fused-variant-p-350.html
and this
http://www.screwfix.com/p/kewtech-kew1700-voltage-tester/61568
Which will also test for open and closed circuits.
It indicates voltage ranges rather than values and is self proving.
Di-Log do a similar unit a little cheaper.

 

[Monkeh]

By the way, the "big bang" and "little fuse" points sound contradictory. Surely you can only make a little bang when blowing a 300mA fuse? To do that I'd need to have the meter set to either AC or DC current, and have the +ve lead in a different socket. I'm not going to try that to see how big a bang it makes.

An improper fuse on a circuit with a very high rated breaker or fuse (ie. before your MCBs) may fail to interrupt the current. This would have fatal effects on the multimeter, and rather bad ones on your hand. There are also other concerns with very high energy circuits (an inappropriate and inappropriately used multimeter caused an arc between unprotected phases, resulting in the death of the operator and significant damage to the building, in one notable incident).

Was that on 240V? In a system with say 300mA fuse in the meter, 32A MCB on the circuit, and 100A supplier fuse, surely it's going to be the 300mA fuse that blows. Aren't the upstream breaker/fuse ratings irrelevant at that point? Otherwise what's the point of correctly fusing a piece of equipment?

That incident was, I believe, 480V across phases at a transformer. There was no fusing whatsoever present.

If your 300mA fuse blows and fails to contain the arc, things go bad. Do not assume the fault is small in magnitude because the fuse is small.

 

[JohnW2]

In a system with say 300mA fuse in the meter, 32A MCB on the circuit, and 100A supplier fuse, surely it's going to be the 300mA fuse that blows. Aren't the upstream breaker/fuse ratings irrelevant at that point?

Yes, one would certainly expect the 300mA fuse to blow. However, that in no way means that only 300mA will have flowed. The magnitude of the current during the very brief period before the fuse blows is dependent upon the fault, circuit and supply, not the fuse. If the situation is such that the fault current is, say, 500A, that's how much will flow through the circuit, including the 300mA fuse, until the fuse blows. As has been indicated, although it might be 'painless', the blowing of a 300mA fuse by a 500A current can also be a very dramatic event.

It's a bit like the widely-believed myth that a 30mA RCD will limit the magnitude of an electric shock to 30mA. In both cases, all the protective device does is to limit the duration of the fault current - the magnitude of that current, for however long it lasts before a protective device cuts it off, is determined by other factors.

Kind Regards, John

 

[aesmith]

My feeling from the thread so far is that I should forget the "voltage pen", but look instead for a set of GS38 rated probes for the Fluke. I think a set of decent probes and a decent meter is better use of my cash than a cheap dedicated tester. Anyone disagree? I accept that a decent tester would be better still of course, but cost has to be a factor.

 

[ban-all-sheds]

Get the leads for the Fluke, and look on eBay for one of these:

 

[JohnW2]

My feeling from the thread so far is that I should forget the "voltage pen", but look instead for a set of GS38 rated probes for the Fluke. I think a set of decent probes and a decent meter is better use of my cash than a cheap dedicated tester. Anyone disagree? I accept that a decent tester would be better still of course, but cost has to be a factor.

Some will undoubtedly disagree but, certainly given your parameters, I wouldn't.

Kind Regards, John

 

[JohnW2]

Get the leads for the Fluke, and look on eBay for one of these: ...

You're trusting electrical products from eBay today?

Kind Regards, John

 

[ban-all-sheds]

I don't believe there's a problem with counterfeit Martindale voltage indicators, distressed and misleadingly sold as used examples of the genuine thing.

 

[JohnW2]

I don't believe there's a problem with counterfeit Martindale voltage indicators, distressed and misleadingly sold as used examples of the genuine thing.

Your belief may well be correct, but .....

Kind Regards, John