Inspection & Testing Fault finding & diagnosis

[Craig2022]

Hi, my name is Craig.

I have been doing electrical for about year+ but only started college about 10months ago.

We have began the new unit of fault finding etc, and I am finding it quite difficult at the moment, and wondered if anybody had any video/reading material that is going to help me.

I was doing a little quiz sheet on Friday, and it was questions about a ring final circuit test.

P & N P & CPC Result/reason
A 0.26 ohms 0.26 ohms Okay?
B NO READING 0.25 ohms Neutral disconnected?
C 0.35 ohms 0.24 ohms Loose neutral?
D 0.24 ohms no reading Cpc disconnected?
E 0.26 ohms 0.26 ohms okay?

That was how the quiz was, and they were what I presumed to be with the results.

Any help would be appreciated, it is a hard unit and expected to have a practical exam for fault finding by April/May, so just trying to get a real understanding of what readings can mean etc.

Thanks

 

[Pete999]

Craig I think the red stuff has had some effect after a long lay off, can't seen to make head nor tail of the questions

 

[Leesparkykent]

Does the question state what cables are used..2.5 t&e, singles in conduit/trunking etc?

 

[Pete999]

Does the question state what cables are used..2.5 t&e, singles in conduit/trunking etc?

Beat me to it mate are the readings he is on about r1 rn 0.26 ohms each and r2 0.26ohms that would answer your question I think but no mention of how the RFC is wired.

 

[Leesparkykent]

Beat me to it mate are the readings he is on about r1 rn 0.26 ohms each and r2 0.26ohms that would answer your question I think but no mention of how the RFC is wired.

Could be or possibly R1 plus Rn and R1 plus R2.

 

[Pete999]

Could be or possibly R1 plus Rn and R1 plus R2.

Makes a bit more sense

 

[Adam W]

Judging from the readings the CPC is the same CSA as the live conductors. If it were wired in T&E I would expect the reading for L-CPC to be a bit higher than L-N.
Apart from that your answers look OK.

 

[Craig2022]

The worksheet was called 'ring final circuit test problems'.
The L & N readings and L & Cpc readings.
I just wrote was was all on the sheet.
It doesn't indicate cable size or any thing, but I'm going presume it's 2.5 with it been a ring.

Where I have put a question mark after the word, is what I believed about the readings.

There was 5 separate results. Which I gave in A,B,CD,E.

I tried to upload picture of the sheet but no use.