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Topic Title: 2395 Question Help please
Topic Summary: 2395 Written Zs Question Model answer please
Created On: 30 January 2013 01:14 PM
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 30 January 2013 01:14 PM
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JJH

Posts: 1
Joined: 30 January 2013

Question ( worth 15 Marks )
Describe how a test for earth fault loop impedance, by direct measurement may be carried out on a circuit supplying a three-phase steamer .

My answer would be
I would not measure Zs on this circuit as it would contravene EAW Safe working practices. The value for Zs can be achieved without working near live conductors by R1+R2+Ze.

Comments :- I guess my answer would not get me 15 marks !

Can Anyone out there give me a Model answer to the question ? i.e. What are the examiners looking for ?

Thanks
 08 February 2013 02:07 PM
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marclambert

Posts: 309
Joined: 23 June 2010

The clue is in "direct measurement" so it is a live test!
1 seek permission
1a signs/barriers
2 correct instrument and scale
3 calibration condition and operation
4 leads to GS 38
5 test between L1 - E
6 test L2 -E
7 Test L3 -E
8 record highest reading
9 reinstate circuit
10 compare readings to OSG or BS7671 corrected to 80%

No one really knows but that's a fair place to start I reckon.
regards
Marc
 01 May 2013 04:31 PM
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saf

Posts: 37
Joined: 26 February 2009

Hi mate,

Im sitting my 2395 online assessment, soon ive been revising chapter 2 initial verification, 3 periodic inspection are they the two actual part i need to revise from...

ive done the online assessment practice my results are always coming up with 83% obvious im aimining full marks 100%, i just want tomake sure dispite getting reasonable results....is it enought to revise from the two sections only?


regards

surfraz
 05 June 2013 09:09 AM
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drmiddleton1

Posts: 8
Joined: 15 March 2013

I did 2391, so can't help with what to revise.

But the answer from Marclambert is bob on. Also mention furthest point of circuit needs to be tested.

Remember, Zs on a live installation changes as opposed to Ze + R1 + R2, as you can have several parallel earth paths bringing down the Zs value.
 05 June 2013 08:06 PM
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deapea

Posts: 369
Joined: 13 May 2007

I would mention about testing up to the live side of the contactor with the control circuit off as opposed to testing at the motor terminals.
 05 June 2013 08:57 PM
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drmiddleton1

Posts: 8
Joined: 15 March 2013

Originally posted by: deapea

I would mention about testing up to the live side of the contactor with the control circuit off as opposed to testing at the motor terminals.


Yes, sorry. Contactor rather than the motor terminals.
 26 November 2013 10:05 PM
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saf

Posts: 37
Joined: 26 February 2009

Hi guys i passed my c&g 2395 got 85% for online and passed my practical and the test of 10 faults from 7 pictures coding them between no fault/c1,c2,c3.

Now i got my written coming up i need help on what to revise in order to pre pare for the exam, important reading guidance note 3, part 2,3, also i need to revise my equations what part will i find that in.

Could some one please advise.

Thanks Surfraz
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