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DoBBY
Does the assessor actually need to see you use a proving unit?
Discuss Proving Unit - Napit assessment in the Certification NICEIC, NAPIT, Stroma, BECSA Forum area at ElectriciansForums.net
never once been asked but i carry one in my tool kit - you never know
Hi.
Sounds like a pain in the bum, but on larger installations this process is safe and pretty much fail proof.
Its what it says on the tin....."safe isolation".
No such thing as "proving dead" really. Say there are multiple supplies and you "prove dead" and then find that it has been re-energised when you are working on it. Safer isolation procedure perhaps rather than safe isolation procedure.
I won't argue with that comment Risteard.
Do you have a better procedure than the one I have posted?
Testing at regular intervals on large installations is surely one way.
Im interested in your thoughts.
Proving unit or Known supply, The latter is free
Okay, this is being picky and my head is full of books at present (it won't be for much longer).
But this is the truth of it.
Someone, one day, will use the supply as their 'proving unit'. They will test the supply as 'live', they will isolate what they think is the supply, they will re-test on their 'dead' supply and during that time their voltage meter will have failed, be it batteries or mechanical failure. Then they will assume the supply is dead....and it isnt.
Stranger things have happened and its the law of averages that such an occurance will happen.
Im only playing devils advocate here. This is unlikely to happen, but this is why 'proving units' are the recommended way of showing your voltage meter is operating correctly, hence proving isolation of the circuit you are going to work on, and protecting your safety.
So, Mattmoo......your 'known supply' is free alright, unless the batteries run out just at the wrong time, then it could be pricey.
not someone using a PC then?...Hi.
Safe isolation as required to pass the 2391 examination is as follows...
* Gain permission to isolate (there maybe someone in a lift etc).
* Identify the circuit to be isolated.
* Isolate the circuit.
* Lock off the supply.
* Add warning labels at isolation source.
* Check your voltage tester with a proving unit.
* Test isolated supply terminals.
* Re-test voltage meter with proving unit.
Sounds like a pain in the bum, but on larger installations this process is safe and pretty much fail proof.
Its what it says on the tin....."safe isolation".
Regards.
Reply to Proving Unit - Napit assessment in the Certification NICEIC, NAPIT, Stroma, BECSA Forum area at ElectriciansForums.net
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