2391 exam tonight

[Steve D]

Well, how did you get on ?

What was the scenario ?

Cheers
Steve

 

[WayneL]

Hi,

Think I did alright - knew everything that was asked - the only
problem I found was the time - it flew by. I managed to answer all the
question but my hand was aching towards the end lol
Didn't have chance to check any answers over as I took the whole 2.5 hours
to finish the questions.

The scenario was a multi story car park.
New DB and Rewire of the fluorescent lighting circuits on each floor in SWA -
ground floor controlled by photocell.
Newly installed ring final to the offices.
Normal questions -

Name two types of inspection applicable to installation.
Certs to be issued on completion (6 marks)
Detailed description of IR test on ground floor lighting (15 marks)
Description of ring final continuity and expected results
and.... the good old earth fault loop path diagram (tn-s) (15 marks)

I enjoyed it, anyway - just hope I gave enough information.


Cheers,


Wayne

 

[Sparky75]

Yep did mine tonight to, thought it was sneaky putting in the figures for both 2.5mm and 1.5mm and then putting in the blurb that all circuits were wired in 2.5mm.
The only question I struggled with was the 5 pointer on checking the swa's on the tray.
Fingers crossed (along with everything else)

 

[Risteard]

thought it was sneaky putting in the figures for both 2.5mm and 1.5mm and then putting in the blurb that all circuits were wired in 2.5mm.

Very dirty trick but they didn't catch me!

 

[WayneL]

Hi Sparky75,

I know what you mean about the five points on SWA,

I managed to think of 5 things to inspect easily enough - it's just
that my answer didn't seem to warrant the 15 marks on offer - unless they were
just giving us an easy 15 marks after the IR test question

Wayne

Another question I wasn't too happy about was:

Who is responsible for recommending the interval to the next inspection?

Guidance note 3 actually contradicts itself on this -

On pg 19 sect. 2.5 it states that the person carrying out the inspection and
testing is responsible yet on pg 87 note 7 it states that it should be a
joint decision between designer, installer and other relevant parties -

So, which is it?

An unfair question, I thought.


Wayne

 

[Risteard]

I thought that question was slightly unclear, but stated that a Competent person was responsible for specifying initial interval, and that it formed part of the Design criteria (i.e. Designer). However as you say there seems to be conflicting advice as to whether it is the Designer or Inspector.

 

[Steve D]

With regards to who is responsible for recommending intervals between testing:

Designer responsible for establishing the first periodic following the initial verification.
From then onwards, it is the responsibility of the inspector to decide intervals between periodics.


I'm gutted I couldn't take the exam myself.

 

[Sparky75]

Might have bombed out on that one then, made it the Inspector taking into account the type of installation, it's use and the frequency/adequacy of the maintenance program.

 

[shagg]

Hi gents I did mine last night as well and it seems it was the same one. Can any of you guys remember what you got for the R1 + R2 on the ring

 

[Steve D]

Yes, same exam nationwide.

I wouldn't be too concerned with a particular mathematical answer. They tend to take a view that as long as the working out is correct and shown, then the actual answer doesn't matter too much.

 

[WayneL]

I put the same as you, Sparky75, almost word for word what it says on pg 19
of GN3 - might be 3 points dropped there then

Wayne

 

[Shaw86]

Thought the question on the earth electrode was tricky. Think the answer was 60 meters from a 3m Electrode and a minimum of 3 tests.

 

[am1]

Isnt it 30m, 10 times the length of the electrode under test?

Thought the scenario was a bit tricky, was they both new circuits, one a new ring circuit and one a rewire with a new dis board, or was the later a periodic?

 

[Risteard]

Isnt it 30m, 10 times the length of the electrode under test?

Aye. The current electrode goes ten times the distance of the electrode under test away, i.e. 30m. The potential electrode goes half-way between them. Then it is moved 10% in either direction (3m). Minimum of 3 tests.

 

[WayneL]

Thought the scenario was a bit tricky, was they both new circuits, one a new ring circuit and one a rewire with a new dis board, or was the later a periodic?

Yeh, I took it that an EIC issued for the new ring final, new DB and wiring and then a periodic carried out on the existing to ensure everything ok after addition and alteration - thats what it tells you in GN3,
anyway


Wayne