testing between selv & bandII circuits

[brucelee]

Hi to all,
I have a 2391 question i am getting a little confused?
question a test to verify seperation between SELV circuit and BANDII circuit state the
a) test voltage to be applied
b) Two tests to be carried out

please can someone clue me up is it
a) 500v
b) insulation resistance between selv live conductors connected together and band II connected together
and insulation resistance between lives of selv connected together and protective conductors of band II

 

[acat]

SELV
1st test at 250V
SELV & Band 2
2nd test 500V


I think thats what you are after pages 40 &41 GN3


Chris

 

[brucelee]

thanks mate,
i just practicing a sample test from college and getting confused cheers mate
i have the gn3 here not explained very well
1st test 250v ir between line and neutral of the selv circuit connected together and earth of band II 0.5Mohm min value
and a IR test between selv lives connected together and lives of bandII connected together at 500v 1.Mohm min value
just realized what i was getting confused with so is the above right

 

[acat]

If you havent got it already try Practical Guide to Inspection Testing and Certification by Christopher Kitcher ISBN 9780750684491.

250v test on secondary side of transformer

500v test is between primary and secondary windings you join the ends of the primary winding together then join the secondary windings together test between the joined ends.



Hope that helps


Chris

 

[brucelee]

cheers mate,
i have niceic eic guide to inspecting and testing, OSG, GN3, BS7671, exam success various sample papers this was a question of one of the sample papers i got from college.
I have been revising for about 16 week as i am doing a 2391 course at bury college 1 evening a week we are half way through. The tutor has said he will give us the answers, but i just wanted to get used to the way C&G ask questions. thanks for your help i just practicing for exams, i will get the book you suggested.
On a selv circuit min insulation value is 0.5Mohm what is the value before further investigation is it 5.0Mohm thanks for your help mate.

 

[acat]

5.0 is correct when getting used to C&G papers you have heard the old saying measure twice and cut one no doubt similar with the papers read twice answer once its the usual thing where an if, not or something similar changes the whole context of the question.

Good luck


Chris