Safe Isolation

Pete999

Pete999

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Just like to get your vies/opinions on modern day voltage testers.

https://www.google.co.uk/search?q=s...t=firefox-b&gfe_rd=cr&ei=WmyLV7yIJsSFaNL0tKAH

The likes of those shown in the link, I was brought up with the John Drumond type, where to be able to prove safe isolation had been achieved you needed a proving unit.

Personally I have never used anything but my old trust JD set up, I was chatting to a newly qualified Electrician, and the question of safe isolation came up, he proudly produced is Stienel tester and when I asked him what sort of proving unit he had, all I got was a blank stare, he said his tester doesn't need to be proved using a proving unit, it is self proving and proceeded to show me.

Now comes the question, and to be honest I'm not sure of the answer, in my opinion and I could be wrong, all the internal test prove is that the electronic circuitry is working OK. Would love to hear some of your thoughts. Should they be tested with the use of a proving unit, as I said I have always used a JD indicator so I have no experience of the Stienel type.
 
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I still got my JD and proving unit, but we use an approved voltage tester these days, the one I have in my kit is the megger dcm340, which is a good meter. Never used any type of self testing item, don't think I would like to either.
 
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Yes all its doing is checking the internal circuits and less
I've had a steinel 1146 since I started and a few people have looked at them and wrongly assumed that they can self prove.....
I just asked them how they thought it could produce 400 AC/DC from two 1.5v DC batteries!
Nobody's answered yet!

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HandySparks said:
Perfectly possible. I bet you don't fit 500V batteries in your IR meter! [emoji14]
Click to expand...
Yes fair enough you've got me there, it could be done, but I suspect the unit would be a bit bigger than it is, and wouldn't allow too many tests !
But the point was that it's not a self proving device in the sense that it produces voltages in its test range




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I would like to know exactly what the self test function actually did before trusting it.

I use the DiLog two pole tester, because I always have and am familiar with it. I've tried other ones but haven't yet got on so well with any of them.

I think the problem here is the one which plagues the industry, and the wider community at times. A lack of understanding, or care for the background information/knowledge. There seems to be a general lack of interest in anything much more than doing the minimum necessary, trusting everything your told without thinking about it, and then going home on time.




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DPG said:
You can indeed if you have a live still available after switching off. Daz
Click to expand...

All you need to do is switch back on to reprove, then isolate, then test for dead. Then reprove by switching back on. Then..... err, isolate and test for dead. Then reprove by, ummm... switching back on.

It's all coming back to me now. I got stuck like this for 6 hours once and had to ring my mate to go and buy me a proving unit. :D
 
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Andy78 said:
All you need to do is switch back on to reprove, then isolate, then test for dead. Then reprove by switching back on. Then..... err, isolate and test for dead. Then reprove by, ummm... switching back on.

It's all coming back to me now. I got stuck like this for 6 hours once and had to ring my mate to go and buy me a proving unit. :D
Click to expand...

I think the idea is you can isolate one circuit, but use a still-live circuit for proving. Doh. Daz
 
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I've got JD with provng unit and other type tester for belling out cables etc.I am shocked these days with to turn up on site these days to help so called electrician to find fault to earth with one,got all the other kit battary dills and big dewalt radio etc no test equipment just turns on electric don't trip out must be ok then.
 
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Stienel make some great kit,and i had an early two pole tester as a youth.

It had AC and DC scales,polarity indicator and a "self-test" feature.

This function was always understood to be ONLY a test of the scale indicator LED's,and NOT of the devices ability to detect voltages across that scale.

I am pretty sure the instrument instructions stated this,also.
 
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If the voltage indicator has 2 forms of indication, ie sound and visual and is classed as self testing then a proving unit is not necessary.

So I was taught on my 2391 some years ago and I've stuck with that since.

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Brightspark2 said:
If the voltage indicator has 2 forms of indication, ie sound and visual and is classed as self testing then a proving unit is not necessary.

So I was taught on my 2391 some years ago and I've stuck with that since.

Sent from my E5823 using Tapatalk
Click to expand...

What standard was given as the reference for being classed as self testing?
There's a world of difference between a manufacturer claiming that something is self testing and a self test system which is safe and compliant with a standard.

Personally I wouldn't put my life at risk on the word of a tutor on a course.
 
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davesparks said:
What standard was given as the reference for being classed as self testing?
There's a world of difference between a manufacturer claiming that something is self testing and a self test system which is safe and compliant with a standard.

Personally I wouldn't put my life at risk on the word of a tutor on a course.
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Depends how your using the word standard Dave.

But confirm with manufacturers data that the unit is self testing, GS38 states that to be complaint, the self test system is listed there as a type of 2 probe tester. This gives compliance with EAWR. A system which is safe and compliant.

But the same can be said for a prooving unit.

What standard was given as reference when advising the use of a prooving unit, theres a world of difference from the manufacturer claiming it works and a system which is safe and compliant such as a known live source.

You see, I imagine there was the same scepticism when prooving units were first introduced.





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Brightspark2 said:
If the voltage indicator has 2 forms of indication, ie sound and visual and is classed as self testing then a proving unit is not necessary.

So I was taught on my 2391 some years ago and I've stuck with that since.

Sent from my E5823 using Tapatalk
Click to expand...

I don't get that at all. The detection circuit could be faulty, in which case neither the LED or the buzzer would operate. You still need to test it. Daz
 
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Brightspark2 said:
Depends how your using the word standard Dave.

But confirm with manufacturers data that the unit is self testing, GS38 states that to be complaint, the self test system is listed there as a type of 2 probe tester. This gives compliance with EAWR. A system which is safe and compliant.

But the same can be said for a prooving unit.

What standard was given as reference when advising the use of a prooving unit, theres a world of difference from the manufacturer claiming it works and a system which is safe and compliant such as a known live source.

You see, I imagine there was the same scepticism when prooving units were first introduced.





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Click to expand...

I man standard in terms of a recognised standard such as a BS or international equivalent.

A proving unit doesn't have the same problem, it is applying a voltage to the test probes and causing the normal indication of a live circuit from the tester. If it doesn't work then it will be obvious.
 
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The confusion here I think is that Brightspark is talking of the tester having a self-test function. Yes, it does - short the probes together and all lights and the buzzer will light up/sound. This however is different to using a proving unit or testing the tester on a known live source. My Kewtech has a self-test function, but it still needs to be used with a proving unit for the safe isolation process. Don't confuse the two things. Daz
 
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Pete999 said:
My old mentor use to lick his fingers, and dap it on the connection, lol
Click to expand...

One company i was at the manager/designed of hearing aids was testing the circuit with his finger. Lot lower power tho (he dose know that's turned on dosnt he!? Yep!) well the guy did suave WW2 In Belgium
 
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Regardless of the detail of the current test device standard,it is surely obvious,that a test of whether or not a potentially lethal voltage is present,is double checked,with a likewise voltage.

The internal checking facility,in the devices discussed,does not do this.

A Lion blood/alcohol test machine,is calibrated with guess what...

...or would a quick rub with a wine-gum,suffice? :dozey:
 
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Pete999

Pete999

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Safe Isolation
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