Quick 2330 Practical Exam Question

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russ9898

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Hi guys,

Ive got my 2330 level 3 testing exam coming up on Monday. Quick question, would someone explain to me how to do the figure of 8 ring circuit test?

Am i correct in thinking you link -

Live on cable 1 to neutral on cable 2

Neutral on cable 1 to live on cable 2

Thanks for your help, Russ

 

SPECIAL LOCATION

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Hi guys,Ive got my 2330 level 3 testing exam coming up on Monday. Quick question, would someone explain to me how to do the figure of 8 ring circuit test?

Am i correct in thinking you link -

Live on cable 1 to neutral on cable 2

Neutral on cable 1 to live on cable 2

Thanks for your help, Russ
Hello Russ9898...

welcome sir. (thats me posh telephone answering voice.. bit like the sort of thing your mom does when she picks up the phone! ; \ :D )

You are absolutely correct in your thinking.

Obviously you would do a quick check to verify individual continuity of each of the Live & Neutral legs around the ring first..

otherwise you are bolloxd ! :_|

Then by crossing the wires as you describe..

You actually construct a continual loop of copper conductor with the same cross sectional area along its entire length.

Because it is now one continual loop measuring continuity across Live and Neutral at ANY point in the ring

The values will be substantially the same. i.e. all sockets = each other AND at the CU.

The value should be approx one quarter of resistance of Phase & Neutral. i.e. (r1 + rn)/4.

If there are any spurs the reading will be higher.

But if there are any bridges across the ring, making a figure of "8"

then the values will vary considerably dependant upon which part of the figure "8" the socket you test at is in.!

Best of luck with the exam m8! ;)

Think thats all come out as my brain was thinking it....

but it is getting late!! :( :p :p:p? :|

 

russ9898

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Thanks SL for that, its pretty much exactly as i thought it was. I just wanted some confirmation to put my mind at rest.

I'm fairly hopeful as a few of the lads in my class took their exam today and imo in class they were clueless. Fingers crossed non the less.

Thanks again for your help

Russ

 
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Hi Russ,

dont forget that when you are linking live and neutrals from one cable to the other that this is only the 2nd part of the test.

Your first part is to measure end to end of phase,neutral and cpc conductors and to note down these readings as r1, rn and r2.

The last part is to link phase from 1 cable to cpc of other leg and vice versa with other phase and cpc.

Then measure continuity using a "low reading ohmeter" between phase and cpc at the CU where you have connected the cables with choc blocs and also at every socket on that cct.

The highest value recorded will then be your R1+R2 value that you record on your test sheet.

 

russ9898

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All done guys im pleased to say.

Nerves got the better of me this morning and i only got a pass. I was put out slightly as the previous person to use the rig hadn't completed the fault finding task (admitted defeat and walked out of the exam). This meant the examiner had forgotten to reset the faults so the first thing i tested...no continuity of cpc which i must admit threw me as i just wasnt expecting it.

Luckily in the afternoon i got my act together and got a credit on the fault finding section of the exam, wasn't far off distinction although i was thrown by a neutral fault which took me a while to sus so got some marks deducted for that. Not to worry though im still pleased with my results.

Thanks for your help special location and cblearnersparks.

 

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