2394 written exam 17th April 2013

chrissimm · Apr 17, 2013

Hi All,

Just sat the 2394 written exam tonight. I thought I done ok but there were a few parts I was left wondering with the wording of the questions. Section A was the tricky part for me this time. Section B normally the tricky section was actually ok.

The only part I got out the room was some scribbles of my working out for a part in Section B.

I think it was a 42 metre loop with Line and Neutral being 2.5mm and CPC being 1.5mm.
The 2.5mm cable was 7.41mOhm/M and 1.5mm was 12.10mOhm/M.

It asked to calculate r1, rn and r2 resistance as - 0.3Ohm for both r1 and rn and 0.5Ohm for r2.

So I then got line to neutral to be 0.1556Ohm and R1+ R2 calculated out as 0.204Ohm.

Ze was 0.3Ohms so to get Zs I added Ze to R1 + R2 and got 0.5Ohms.

The questions that puzzled me were the ones about what would you verify on basic and fault protection for SELV, Separated circuits, Insulation etc. How would you veryify them.

Sorry cannot remember the correct wording.

Cheers Chris

jeffelectric · Apr 17, 2013

same paper here too, separated circuits wtf

chrissimm · Apr 17, 2013

Everyone to a man left the room discussing those questions and how they didn't get the wording and what C&G were looking for.

lesterwyatt · Apr 17, 2013

I found tonight's 2394 easier than last nights 2395! Still hard though

Pondy · Apr 17, 2013

My third time of taking, didn't really get the first section, am I right in thinking the pass mark varies depending on how everyone done?

chrissimm · Apr 18, 2013

Pondy said:
My third time of taking, didn't really get the first section, am I right in thinking the pass mark varies depending on how everyone done?

I hope so because everyone I spoke to didn't get the same parts of the first section

JamesMcBride · Apr 23, 2013

Just thought I would reply to say that I also did the 2394 exam on the 17th - I also wasn't really sure what to put for the "what to check for protection by SELV"

I think I put somthing along the lines of:
- that the equipment providing SELV conforms to the relivent bristish standard
- that the SELV circuit is electrically separate from the rest of the installation
- that the SELV circuit is operating at extra low voltage

To be honest I had a complete mind black on that question, I thought that the rest of the paper was fairly reasonable though. I did think the three or four "what to check and what to check for" questions were a bit stupid though.