2391:301 Theory Exam Tonight 15th March 2012

[wams]

Hi All,

Is there anyone including myself who sat the exam have any feedback on tonights paper and have any questions about any questions in the paper that you feel can be discussed

Wams

 

[sparkysam]

Found it quite straight forward, well, I say that, il be sitting a resit in a few months

 

[wams]

What were the questions, any good ones ?

Section B Scenario

An office wired 12 years ago, 230/400V 3 phase, BS88 100A main fuse, wired in pvc singles in pvc conduit and trunking.

5 metal bollards in car park wired in 2 core SWA controlled by a time clock and contactor.

3 phase board next to the service head, TN-S earthing.

A new occupier had just moved in and an EICR needed to be carried out, tested at 20

 

[Technician]

What about a live Zs to the bollards with PFC test

conducted after a dead (R1+ R2) test?

 

[bazbithell]

Initial inspection of lighting.

What looking for and why. 15 marks

Another one was,

Selv circuit coming off a 400v board

What was the test voltage and minimum meg reading. Or something like that.

 

[sparkysam]

In order of sequence, what other 3 tests are carried out after an earth electrode test? Something along those lines, what did you guys put?

 

[bazbithell]

The wrong answer

 

[mneale1]

What are 5 checks to be carried out on the car park lighting, give detailed explanation how to do each check. (words to that effect)

 

[azm]

I Pressumed they meant visaul inspection on the lighting circuit for that question, but you never no with them.

 

[ashleycowx]

I remember a question about SELV

A SELV circuit is to be insulation resistance tested connected with a 400v 3 phase motor.

What voltage tested at.

What minimum result.

Something like that anyways.

I put Link L-N and test to earth at 250V DC and minimum of 0.5MOHM.

I know theres a 400v 3 phase circuit but SELV was mentioned!

 

[azm]

i tought if was tested to the live conductors of a 400v circuit you test to hight circuit pressent ie 500v and min of 1 M ohm, well thats what i put anyway. It mentions it on page 41 of gn3.

 

[leonard]

2391 4.pdf

good luck to everyone

2391 1.pdf

2391 2.pdf

2391 3.pdf

 

[Hilldog]

I put the 3 special locations in a house as bathroom, solar voltaic and under floor heating. Not sure if would ave got the marks for sauna and swimming pool.

Struggled the most with the checks on the the car park lighting. What did anyone put for that?

Also struggled with why there were 6 marks awarded for what docs should accompany the inspect and tes for new premises. I just got it as PIR, schedule inspections and test results. Was this a trick or did I miss 3 more? (also does anyone know if we will. E marked down for using PIR and not the new for from the new regs EIRC or something??)

The insulation resistance test on a ring final circuit is jus the same as any other IR test right?

Main one that is driving me crazy tho is Q8. State one point eclectically connected to the MET by each of the following

A) CPC

B) main protective bonding conductor

C)earthing conductor

I Just don't know the answers to these. Anyone help me out??????

Cheers

 

[Wod81]

CPC is exposed conductive parts

Bonding extraneous eg water pipes

Earthing conductor I put supply electrode

Lights I put:- check termination of glands, banjo's with fly leads for earthing

Identification of conductors tightness of terminations

Lights not damaged or corroded comply with BS suitable for intended purpose

Routing of cables, support of cable to relieve stress on conductors

---------- Post Auto-Merged at 21:06 ---------- Previous post was made at 20:41 ----------

How did you manage this?

Where's questions 12-20 ??

 

[Hilldog]

All the questions are there in PDF format above (Look carefully). Might have to be logged in tho.

For lights check I put

Check Voltage drop using calc (pretty sure this is wrong)

Check metallic colums properly earthed

Check luminaries for thermal effects

Check all joints/glands on SWA eclectically and mechanically sound

Check CPC is corrosion free and therefore effective.

Not great answers. I think yours are better. They should have asked us to draw an Earth fault loop diagram instead !!!!!

Wasn't too sure on the surge protection IR test either. Our tutor said that it's only 250v and 0.5Mohms if they say the word SELV. I put 1M ohm and 500v for surge protection on this basis.

---------- Post Auto-Merged at 20:08 ---------- Previous post was made at 20:03 ----------

In order of sequence, what other 3 tests are carried out after an earth electrode test? Something along those lines, what did you guys put?

I put

PFC

Zs

Phase rotation

What did you put??

 

[Wod81]

Found them wasn't lookking properly.

Your ev must have been sleeping!!!!!!

An Earth Fault loop diagram or Insulation resistance of whole DB calc would have been better, For SPD it's 250v but 1M ohm

for tests after Earth electrode I think I put Zs, protection by ADS and PFC

Thought question 20 was strange would that really happen?

Did you mention the contactor/time clock on the R1+R2

 

[Hilldog]

Nah didn't mention anything about the clock for R1+R2. What were we supposed to write?

I know you don't get any marks if you don't say the word metallic when describing path to earth on TNS as metallic earthing sheath

The answers that are scribbled on the PDF copies of the tests? Who wrote them? Are they accurate answers cos I get different answers for some of them.

What do you reckon is the pass mark??? I know it's a floating one but in guessing 70%.

 

[studentspark]

View attachment 3260Here is the March paper ,ignore the handwriting .View attachment 3257View attachment 3258View attachment 3259good luck to everyone

Your 2391 4 pdf do not work. can you re-upload it?

 

[Wod81]

Don't know who wrote them, there are different answers you could put for some of them.

With the R1+R2 I think you should mention the contactor and time clock about linking them out so you can obtain a result. Think that's why they put it in the scenario, but that's just my opinion.

I got told by my lecturer the pass is 80%

 

[Steve B]

I got told if you can get 95 marks you will pass