NAPIT Certification Scheme Proving Unit - Napit assessment

[DoBBY]

Does the assessor actually need to see you use a proving unit?

 

[ezzzekiel]

never once been asked but i carry one in my tool kit - you never know

 

[IQ Electrical]

never once been asked but i carry one in my tool kit - you never know

I'll second that.

 

[steamboatwilly]

I'm NICEIC and I've been asked to use one a couple of times as part of the safe isolation procedure.

 

[SPARTYKUS]

If its your first assessment and you've got one and you're a sparky, then you should use it He's not going to think you're trying to impress him!

Just make sure the batteries aren't flat before ..... and take your time, and look as much up as you like. Nothing worse than guessing. Good luck chap!

 

[sjm]

I'm NIC and my assessor hasn't asked fro a proving unit. TBH you've got one at the incoming supply to a consumer unit.
Test live-neutral and live-neutral to earth. Switch off main switch. Test live-neutral and live-neutral from bottom terminals of main switch (or disconnected terminals). Then retest live-neutral and live-neutral to earth on incoming to PROVE continuing correct performance of your voltage tester.

Hope that helps.

 

[topquark]

Only time I've had to use one for proving safe isolation was when the DNO actually had a means of isolating between meter and CU and had used that as the isolation point. Otherwise using the incoming supply is OK.

 

[PJK]

Hi

I am NICEIC and was asked to present and demonstrate proving unit in my first assessment. Not asked since.

 

[mattmoo1974]

Proving unit or Known supply, The latter is free

 

[SMB]

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.

 

[Risteard]

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.

 

[SMB]

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.

 

[Risteard]

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.

Wouldn't like to say that I have a better procedure than the industry recognised one, but just wanted to point out that it does have its limitations. I always assume that something is live even after "proving" dead.

 

[SMB]

Good practice mate.

I wish you well.

 

[SMB]

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.

 

[Clark3169]

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.

Unless your approved voltage indicator will work even without batteries. Just like this one

Martindale VT12 Voltage Indicator

i thought most did to be fair?

 

[varilite]

If its just a pure voltage tester no batteries but if it also does clever things like continuity it will require batteries

 

[Clark3169]

That makes sense. Thanks.

 

[GLENNSPARK]

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.

not someone using a PC then?...

wheres your lockoff key going?....an instant fail on the 2391 if you dont do this

 

[SPARTYKUS]

2391? Whats that :wheelchair:

(got mine and no ones having it!)