tonights 2391 exam....(10th march 2011)

[lynj]

one thing to say and that is did c&g forget how to be staightforward? felt like some of the questions were half thought......

anyone else take it?

 

[malcolmsanford]

500mA Rcd? , is for Fire protection and not shock protection, BS7671 requires special locations I.e marinas to be additionally protected by 30 ma or possibly tine delayed 30ma, I went for 30, I'm not sure if I'm right

Sorry but no such animal, though would be a good one to invent.

 

[LlandrilloSpark]

Hmmmmm, damn that was my take on it and some very respected people I know, certainly not 300 or 500 anyway!

 

[LlandrilloSpark]

Can I point people to section 709 in the regs "marinas" then reg 709.531.2 then redirect to reg 415.1.1

30mA for me

 

[chrissimm]

Hi Guys,

Newbie posting I sat the test on Thursday as well and by question 26 my mind was pickled anyway but I did pick 30mA. Good luck to all who sat it. It was a stinker.

Chris

 

[Paul.M]

Welcome along Chris.

 

[B6 7BU]

Can I point people to section 709 in the regs "marinas" then reg 709.531.2 then redirect to reg 415.1.1
30mA for me

When you look at 415.1.1 go back to 411.3.3 was it a socket?

Take a look at 411.5.3(ii) and Table 41.5

 

[Gra]

interesting, you read through more in depth and very true it was not for socket protection but for fixed lighting. It told you that the earth electrode was 100ohm and that it was a 61008 rcd. Now although this isnt the main switch of the installation i think they are actually asking you to show you undertsand your methods of working out RCD tripping current ratings

So that would work out 50v (safe touch voltage)/ 100 (resistance of electrode).??????????

That will put a spanner in the works.
Good luck everyone glad i wasnt alone in finding it tough!
By the way thanks for such a great forum, now ive discovered it this is a place of great value!!

 

[IQ Electrical]

I'd really like to see the full question to come up with a full answer, weird that nobody managed to get the paper?

If a paper did accidently fall into your bag, PM me!

 

[filrobbo]

The question from what i remember was what mA RCD would need to be fitted for the lights in the moorings of a marina. The lights were fixed in columns. The columns were fed from a 3 pahase tt supply by a swa. The swa was feeding an RCD at the bottom of the columns with twin flex feeding the lights inside the columns. It was a 100 ohm resistance for the earth electrode.They then asked what tests would need to be carried out on the RCD.
I put 500 mA. Based on the above scenario would I be right????? Think I'm goin mad haha!!!

 

[NMc]

It like IQ says it the paper that is required. I now seen a few version of this question so if someone does manage to obtain the paper I too would like a view

 

[chrissimm]

If I remember correctly the question was worded 'determine' what size of RCD is required for the lights. I done the calculation and was put off by the 500mA result. I then had a brainwave - for good or for bad LOL - that most questions that require a calculation normally start with 'calculate' what size of RCD and it may also have asked for 'show all calculations'. So I may have foolishly have went for the 30mA RCD due to the wording of the question and the odd calculated value.

Speaking after the exam to almost all who sat it question 26 gave everyone problems.

Chris

 

[dazsmith]

I sat the exam on Thursday too and I too was puzzled by question 26. What angers me that you can't even go to gn3 or the regs and get a straight answer so how are you supposed to answer it in a closed book exam??? And why would you ever carry out any work on a Marina install without consulting the regs book first of all???? I understand you need to show understanding but why try and f@#$ you up???

 

[lynj]

exactly, why do a marina location when your almost likely to pull out the regs as its a special location..... i think they wanted to do a different scenario just to trip the people up that expected a bog standard scenario like a block of flats or a domestic location

 

[NMc]

Surely the questions related to testing/inspection which apply in all scenerio's The marina situation was probably to throw you

 

[newby]

I cannot see the value of creating scenarios with the intent of causing confusion. It is very easy to word questions in such a way as to direct people to the wrong conclusions, or put doubt in their mind, but who does that benefit. Exam conditions create a great deal of stress in most people so, in my opinion, clear and concise scenarios are far more likely to elicit a true insight into the knowledge of candidates than ones designed to throw you off track. I wonder how many people knew what a kiln actually is.