June 2011 2391 exam

[Richard]

Did any of you sit it? I didn't think it was TOO bad, couple of questions I was a little unsure of but overall ok. How did you guys find it? I can never think of the bloddy questions afterwards!

 

[Channie12345]

Yes, just sat it, not many calculations, it seem to be a bit easier that past papers I have seen.

 

[dean7828]

think i got the voltage drop calcs for the motor circuit up put 5% but think its 8% how long dose it take for the results to come through

 

[dean7828]

am i right is saying that a 100ma rcd is tested at 50ma and 100ma at 200ms?

 

[Richard]

am i right is saying that a 100ma rcd is tested at 50ma and 100ma at 200ms?

I wasn't sure as i'v read somewhere that you don't perfrom the 5x test, but i could well be wrong!

 

[dean7828]

thats what i thought, 5x would be 500ma test current so way too high

 

[Richard]

Also as it's a BS EN rcd, I think that makes it 300ms

 

[Richard]

What two test do you have to have all circuits Isolated to perform?

I went for continuity of protective conductors, External earth fault loop impeadance

 

[thorneellis]

This was my second attempt since last year, did think it was a lot easier than previous past papers, but then again i thought that last year. No mention of drawing earthing systems. just describe the continuity of gas bond and insulation resistance of lighting circuit if i remember correctly

 

[joe_berks]

am i right is saying that a 100ma rcd is tested at 50ma and 100ma at 200ms?

i remember that question was "what two test currents should be applied to the 100mA RCD?" or something like that. i put 1x and 5x . at 1x it is less than 300ms and at 5x it should be within 40ms

 

[thorneellis]

**** didnt realise we had to calculate the voltage drop i thought it was just after the percentage volt drop acceptable. i wrote 5% for the 240 socket and i thought the 3 phase was 8%............few points gone for me there then

 

[Richard]

What made me think was the half times test though

 

[joe_berks]

damn i put 'continuity' and 'insulation resistance' but i now realise i didnt read the question properly... ALL CIRCUITS isolated. Thought i done well but starting to doubt it now !

 

[Richard]

Where do you get the 8% voltage drop for three phase figure from? I'm stuggling to find that one

 

[Sparky Ninja]

i remember that question was "what two test currents should be applied to the 100mA RCD?" or something like that. i put 1x and 5x . at 1x it is less than 300ms and at 5x it should be within 40ms

Wouldn't that be x0.5 and x1, so 50mA and 100mA?

 

[joe_berks]

appendix 12 of 7671 for the 8% figure.

 

[joe_berks]

oh no it was 5% ! starting to really doubt myself now thought i had it in the bag .

 

[luke]

Just sat the exam myself, found it ok really, first time so fingers crossed. The question on the rcd is 1/2 x test 50mA and 1 x test 100mA 300ms. The only rcd you test at 5x test current is a 30mA rcd otherwise you put to much current into the installation. Is the pass rate 60 % ?

 

[dean7828]

im sure 5x test applies to a 30ma rcd for additional protection and must operate within 40ms

 

[dean7828]

i well got some right got some wrong just hope its enough! not the end of the world if not good luck chaps