2391-10 Written Exam - 01/12/11

[cr0ft]

Just sat this tonight. What does everyone that sat it tonight think of the paper?

 

[fredrico]

I did the 2391-301 tonight, did not think it was too bad, although i know now that i have cocked up a few questions.

 

[exnavysparks]

same same mate

 

[exnavysparks]

Q1 and Q4?????? you know what i mean lol

 

[fredrico]

cant remember, what were they? I cocked up volt drop, in one of the long questions, i muliplyed ib x z x 1.2. Number 1 and number 4, were they the ones about initial verification?? I put the same answer for both, as i knew at least one of them would be correct.

 

[exnavysparks]

something about initial verification that sounded identical :mad2: oh well haha

 

[exnavysparks]

it was a nightmare mate,i attempted to duplicate my answers, then i did some scribbling out and put something else then i rescribbled some more

 

[exnavysparks]

you came in above 5% then? i winged it at got 11.4 and 4.9% but it took me a while to work it out if im honest. the exam is at a funny time of night?!!

 

[brav]

Same here with the Q1 and 4, tht threw me a bit, then Q5 two things about the supply tht only find out from the supplier, I put frequency and earthing arrangement. section B I screwed up on ze test forgot it was a three phase board duh. Guess i'll be sitting it in Feb then lol

 

[cr0ft]

I got 11.4% as well so just within the allowed volt drop. Seemed far too easy for 8 marks though I have to say.

 

[pfjt]

Should I have halfed the combined resistance for the volt drop , also what should I have put for question 1

 

[pfjt]

I got that answer aswell. But I should I have halfed the combined resistance of the line and neutral

 

[cr0ft]

The impedance (or in this case the resistance) of both conductors must be taken into account when calculating volt drop.

 

[pfjt]

Few I got it right then I think. Just thought that 8 marks for it seemed allot. Did you do the exam

 

[cr0ft]

Yes mate. Thought it was a bit tough at first but when I got home and checked my answers against the books I think I've done ok. Fingers crossed!

 

[pfjt]

I'm not sure how I did q1 and 4 not sure wot I should have put aswell as the live working question. Can u remember q1

 

[cr0ft]

I was unsure about a few of those ones, again more due to it not being very clear what they were asking for.

I think the live working question was something like what considerations must be taken prior to working on or near a live appliance. I put: -

1.) Is the live working really necessary?
2.) Can the equipment/conductor be safely isolated?
3.) Are tools etc insulated to a level suitable for the voltages present.

Can't remember questions 1 to be honest!

Just remember that all 3 of those questions, even if you got them completely wrong are only worth 9 marks. As long as you did ok in section B you are most of the way there already. That's how I see it.

 

[pfjt]

Fair point. And yes the way they ask the questions is like a riddle sometimes

 

[pfjt]

Does any body remember q1 and q4

 

[pfjt]

Q21 when it asked fee the documentation for the completed electrical work did it jus want the elec certificate and schedules and not the periodic aswell

 

[Former Sponsor TM]

On Q21 for new electrical installation work I put an Electrical Installation Certificate accompanied with a Schedule of Test Results and a Schedule of Inspections, for the Inspection I put a Periodic Inspection Report for an Electrical Installation, again accompanied with a Schedule of Test Results and a Schedule of Inspections. It carried 6 marks so hopefully thats a mark for each one....

 

[firemanowl]

Q1 I think was the list on page 17 of GN 3?

Q4 was something along the lines of why do we do an initial verification:-
1, Confirm installation/circuit complies with designer's intentions
2, Designed, Installed and Inspected & Tested to comply with BS7671
3, Not damaged so as to impair safety
Just seen it in some notes, not sure where it came from though as nothing in GN3.

Don't you have to add a x1.2 correction factor to the volt drop formula to allow for the rise in temp when the circuit is under load?

Good luck to everyboby, only a couple of months to wait.

 

[SHOCKNOT]

Just sat this tonight. What does everyone that sat it tonight think of the paper?

I like others not too bad but questions 1 and 4 were confusing, I answered Q1 then when i got to Q4 thought isnt that the same as Q1. I answered for Q1 to ensure installation meets relevant stds, e.g bs7671, to ensure nothing in the installation is damaged and to ensure all equip is erected correctly.
for Q4 I answered to protect persons, livestock and property. My worry is that Ive got answers wrong way around.

 

[fredrico]

What was the special location that cant be connected to a TN-C-S system??

 

[Former Sponsor TM]

What was the special location that cant be connected to a TN-C-S system??

I put caravan park

 

[exnavysparks]

I put down caravan site for that one i think?

 

[exnavysparks]

what did ppl put down for the supplementary bonding Q i put agricultural location eventually after a lot of scribbling out and correcting lol

 

[pfjt]

I put bathroom for bonding. And mobile units for the tncs

 

[SHOCKNOT]

Dont know, I put both lots of documentation down but making sure that i said for the initial verification you require a EIC, SOI AND SOR, then for the PIR you need PIR, SOI AND SOR, however the SOI is shared between both (it covers both)

 

[SHOCKNOT]

I put caravans, some caravan parks are connected to tncs but you cannot connect caravans to a tncs arrangement so at some point you convert to tt.

 

[Jurasic Spark]

Q1 I think was the list on page 17 of GN 3?

Q4 was something along the lines of why do we do an initial verification:-
1, Confirm installation/circuit complies with designer's intentions
2, Designed, Installed and Inspected & Tested to comply with BS7671
3, Not damaged so as to impair safety
Just seen it in some notes, not sure where it came from though as nothing in GN3.

Don't you have to add a x1.2 correction factor to the volt drop formula to allow for the rise in temp when the circuit is under load?

Good luck to everyboby, only a couple of months to wait.

Q4 was something along the lines of why do we do an initial verification:-
1. All installed equipment complies to relevent standards.
2. Everything has been selected and erected in accordance with BS7671
3. No visual damage to impair safety
GN3 p17

 

[exnavysparks]

v drop Q.... was it.... (R1+RN) X Ib
0.38 ohms x 30A = 11.4 ???????

 

[SHOCKNOT]

Thats the answer i got 11.4, which i got to 4.95% so I think thats ok because all circuits you are allowed 5% except for lighting circuits (i think?).

 

[Banjo]

For the TN-C-S question i pit down Exibitions, shows and stands.

What did people put down for the max voltage on socket outlets with surge protection devices?

 

[firemanowl]

v drop Q.... was it.... (R1+RN) X Ib
0.38 ohms x 30A = 11.4 ???????

I think you have to apply a x1.2 correction factor to allow for the rise in temp when circuit under load?

 

[firemanowl]

250 v for surge protection

 

[Banjo]

250 v for surge protection

Good thats what i put. Then the next part of the question asked for wht are the test connections i put test between live conductors and live conductors to earth.

 

[firemanowl]

Thats what I put Banjo, i think it's only the test voltage that is different, the rest of the test is the same.

 

[fredrico]

Thats what i put Banjo. Is it a 60% pass mark for the exam? Its a total of 90 marks for section B and about 60 marks for section A ?? So you have to get 60% of 150 marks?? Also 1M ohm minimum resistance for the surge socket is what i put.

 

[Banjo]

I heard the pass mark floats at 60% to 70%, as they mark it so only a certain percentage pass i think. What didyou put for the question that asked the earth return parth on section A with TNCS, TNS & TT?

 

[firemanowl]

What test voltage did you put for the 25v question?

 

[Banjo]

What test voltage did you put for the 25v question?

I put 250v

 

[NMc]

There is no officially stated pass percentage by C&G. It is what is called floating. It depends upon a number of things, the main one being how hard the exam is deemed to be. As a general indicator you need to be aiming for 80% to be OK

 

[fredrico]

80%?? Thats me done for then.

 

[fredrico]

Look on the bright side, at least i have been promoted from Junior Member, to Member!!

 

[Scotchydog]

What did you all put for the two types of instruments that mease phase sequence - i werent sure if it was trying to get the two types of phase sequence testers in i.e the indicator and the digital one something along them lines

all though i just guessed the other one as a method of polarity i.e low resistence(reading) oh meter for DEAD and approved voltage indicator for LIVE

also i think i cocked up on the R1 + R2 on the lighting circuit as i didnt include the photocell just put the extremity of the circuit test r1+r2 and so on

 

[Banjo]

What did you all put for the two types of instruments that mease phase sequence - i werent sure if it was trying to get the two types of phase sequence testers in i.e the indicator and the digital one something along them lines

all though i just guessed the other one as a method of polarity i.e low resistence(reading) oh meter for DEAD and approved voltage indicator for LIVE

also i think i cocked up on the R1 + R2 on the lighting circuit as i didnt include the photocell just put the extremity of the circuit test r1+r2 and so on

For the phase sequence i put rotating disc type and indicator lamp type.

 

[Scotchydog]

yeah i agree that what it says in GN3 but my mind went blank when i read the question, allthough the exam was better than i thought i still think there was a lot of questions that i wasnt expecting just hope ive done enough dont think i got 80% maybe 70+, i will be gutted if i have to take it again

 

[NMc]

With 70+ Scotchydog you may be supprised. Now you have the long wait results due end Jan next year. Here's hoping

 

[ian.settle1]

Same here with the Q1 and 4, tht threw me a bit, then Q5 two things about the supply tht only find out from the supplier, I put frequency and earthing arrangement. section B I screwed up on ze test forgot it was a three phase board duh. Guess i'll be sitting it in Feb then lol

Why would you put frequecy as the whole of the country is 50hz?