IR test 2391 The way to answer ?

[LittleHelper]

Hi guys,

Just wanted to get your advice on answering a 2391 question.


If i was to get a question "Describe how to carry out an IR test on a radial socket circuit of a new installation" for example , would i be able to mention the safe isolation procedure like this

1)Seek Permission /Inform relevant persons test is to be carried out
2)Agree extent and limitations
3) Safely Isolate supply /Lock off
4)Remove or link out devices sensitive to test voltages, Remove lamps and current using equipment
5)Put up barriers and warning notices where appropriate.
6)Test instrument used is an Insulation Resistance tester scale used M/ohms
7)Check test instrument is calibrated, using fused probe lead checking for signs of damage. And is fully functioning.
8)Connect one lead to the line conductor and the other to the neutral conductor, test and record result. Do the same between Line - Neutral and Neutral - CPC Record result
9)Reinstate circuit
10) A reading of 2M/ohm or more would be satisfactory

Now should i explain the whole safe isolation procedure as well as the IR test procedure or is it ok to just mention the safe isolation procedure it just seems a lot to write in such little time. But i obviously want to answer as best as possible without missing anything.

Many thanks

 

[telectrix]

IMO, the question asks you to describe the IR test procedure. it does not ask you to describe safe isolation. your answer above seems fine to me.

 

[LittleHelper]

Thanks for your input telectrix. I thought it might be too long winded but i need to to make sure i can answer and not waste time cheers again!!

 

[Gage]

Hi guys,

Just wanted to get your advice on answering a 2391 question.


If i was to get a question "Describe how to carry out an IR test on a radial socket circuit of a new installation" for example , would i be able to mention the safe isolation procedure like this

1)Seek Permission /Inform relevant persons test is to be carried out
2)Agree extent and limitations
3) Safely Isolate supply /Lock off
4)Remove or link out devices sensitive to test voltages, Remove lamps and current using equipment
5)Put up barriers and warning notices where appropriate.
6)Test instrument used is an Insulation Resistance tester scale used M/ohms
7)Check test instrument is calibrated, using fused probe lead checking for signs of damage. And is fully functioning.
8)Connect one lead to the line conductor and the other to the neutral conductor, test and record result. Do the same between Line - Neutral and Neutral - CPC Record result
9)Reinstate circuit
10) A reading of 2M/ohm or more would be satisfactory

Now should i explain the whole safe isolation procedure as well as the IR test procedure or is it ok to just mention the safe isolation procedure it just seems a lot to write in such little time. But i obviously want to answer as best as possible without missing anything.

Many thanks

Push both probes against your nipples
Select 500V
Press test
A reading of 2M[FONT=arial, sans-serif] Screams or more would be satisfactory,[/FONT]

 

[telectrix]

Push both probes against your nipples
Select 500V
Press test
A reading of 2M Screams or more would be satisfactory,

only 500V?????? pansy.

 

[Gage]

only 500V?????? pansy.

I was recommending it for him. I just walk in to substations and bite the cables.

 

[guest119]

Why do you even mention safe isolation as you have stated new installation. IE never been energised.
On an installation that is not new, always start your l-n tests on 250v then up to 500v.

 

[LittleHelper]

Why do you even mention safe isolation as you have stated new installation. IE never been energised.
On an installation that is not new, always start your l-n tests on 250v then up to 500v.

Very good point cheers

 

[LittleHelper]

Will try that one gage

 

[Toonlad]

I was advised that you bullet point that you .... "Carry out safe Isolation procedure". Then describe with bullet points how to do IR test.

As for new instalation, we know this is pedantic and the whole board would have been dead tested first. But the examiner likes to see it pointed out. Just because its a new instal doesnt mean once your back has been turned it wasnt energised.

 

[SirKit Breaker]

The question will be worded something like as follows.

"Describe in detail, and with the aid of a diagram, how you would carry out an Insulation Resistance Test on a newly constructed radial circuit, after safe isolation has been carried out".

Cheers............Howard

 

[pistolpete]

Gs38 compliant leads, finger guards, no more than 4mm exposed, preferably 2mm... Just an idea

 

[pistolpete]

I'd mention 500v d.c.
If you know what you're doing wouldn't test at 250 first, just the way I was taught though...

 

[LittleHelper]

So if it says "after safe isolation has been carried i take it there is no need to mention it?
Thanks Howard

 

[LittleHelper]

I'd mention 500v d.c.
If you know what you're doing wouldn't test at 250 first, just the way I was taught though...

I saw i missed that out lol. If i was to soft test at 250v due to not being sure if voltage sensitive equipment was still part of the installation would i then (have to test at 500v ) with live+neutral connected together to earth?
Many thanks

 

[Geordie Spark]

I was advised that you bullet point that you .... "Carry out safe Isolation procedure". Then describe with bullet points how to do IR test.

As for new instalation, we know this is pedantic and the whole board would have been dead tested first. But the examiner likes to see it pointed out. Just because its a new instal doesnt mean once your back has been turned it wasnt energised.

Aye ........ I knew a spark who was technically dead after being caught out this way. Fortunately his gaffer manage to save him, but he spent a long time in hospital recovering.

 

[SirKit Breaker]

So if it says "after safe isolation has been carried i take it there is no need to mention it?
Thanks Howard

You have got it. You also need to see what marks are available for the answer. 15 marks, means they want 15 things mentioned that are relevant.

Read the question, and answer it appropriately. If they state "After Safe Isolation" then dont waste time and effort mentioning it, cos you will get naff all marks, it is not relevant. But GS38 test leads blah blah blah, Calibrated Insulation Resistance test meter that circulates .......A for ..........Seconds, at .........test voltage with a resolution of..........decimal places. Visual check of instrument and leads. Confirmation of correct operation prior to carrying out test. How you did the test, test results and how you know they are acceptable or not.

Enjoy,

Cheers................Howard

 

[LittleHelper]

You have got it. You also need to see what marks are available for the answer. 15 marks, means they want 15 things mentioned that are relevant.

Read the question, and answer it appropriately. If they state "After Safe Isolation" then dont waste time and effort mentioning it, cos you will get naff all marks, it is not relevant. But GS38 test leads blah blah blah, Calibrated Insulation Resistance test meter that circulates .......A for ..........Seconds, at .........test voltage with a resolution of..........decimal places. Visual check of instrument and leads. Confirmation of correct operation prior to carrying out test. How you did the test, test results and how you know they are acceptable or not.

Enjoy,

Cheers................Howard

Thank you very much sir and the rest of the guys i think i got this kind of question or similar pretty much nailed much appreciated!

 

[alli]

As others have said you may not need it, but if you do were to include

3) Safely isolate supply / Lock off ... do you need to also state testing and proving the circuit is dead with an approved tester etc. etc.

If you are in a slight doubt about the question, could you cover you arse and have a sentence saying something like: As this is a new installation I assume Permission, Isolation of supply, testing for dead have all taken place. At least this would show your considering the safety aspect.

 

[telectrix]

I assume Permission, Isolation of supply, testing for dead have all taken place.





Never, Never, assume that testing for dead has already taken place. It's your life, YOU test.

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