IR test 2391 The way to answer ?

[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.

​

 

[DJ Ovengloves]

OP, you may want to check out page 96 of the OSG and look at the minimum resistance values!

 

[alli]

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.

​

Fair enough, wrong choice of words.. My point was aimed at answering the exam question that the op had shown to the examiner he had considered the safety side of testing. Maybe a better choice of words would of been:

Ensuring Permission, Isolation of supply, testing for dead have all previously taken place.

I agree In the real world nobody should EVER assume anything they hadn't done themselves.

 

[telectrix]

fair enough.

 

[Mfctitch]

Wow a post where no one is either point scoring or biting the persons head off for asking a question
top marks

 

[guest119]

Thread is not closed yet is it?

Boydy

 

[Jurasic Spark]

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 not relevant to an initial verification
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. GS 38 compliant ???
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 what about Line to earth??
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

This is how points are thrown away in 2391, call it pedantic if you like but thats the way they mark the exam

 

[Silly Sausage]

Also, if it was a 3 phase circuit, don't forget to mention the 3 Line to Line tests.

 

[LittleHelper]

This is how points are thrown away in 2391, call it pedantic if you like but thats the way they mark the exam

Thanks for your input jurasic. GS38 i agree because its a circuit im testing i would just test between (line and cpc) terminology correct me if im wrong.
Many thanks again!

 

[LittleHelper]

Also, if it was a 3 phase circuit, don't forget to mention the 3 Line to Line tests.

Would it go something like this

Test between L1 - L2, L1 - L3, L2 -L3
between L1+L2+L3 (Connected together) - Neutral
between L1+L2+L3 (Connected together) - Earth
between Neutral - Earth ?

 

[Silly Sausage]

Do L1,2,3 to N & E separately.
You'd get a low reading otherwise, parallel resistances.