2391 exam

[trebor]

Hi Peeps
Ive got my 2391 exam on Feb 10th. I was meant to sit in Dec but was snowed off.
Any tips for the exam?

One of the biggest failure reasons is not reading the question properly, not lack of knowledge, for example ive seen the earth fult path drawing by picasso but for the wrong system, highlight your info in the scenario, system,Ze,pfc etc and then write it in list form in the right hand margin, this will give you aquick reference when anwerinf questions, explain the tests in bullet form with at least one line spacing to allow something to be put in if missed, dont bang on about safe isolation procedures when the the question starts for example: an insulation test is to be carried out on a new ring final circuit BEFORE connection to the DB, it is not only a waste of your time but marks can also be deducted, if a question asks for a list of 3 reasons dont write a shopping list, if the corecct answers are not in the first three then they dont count, if a question stumps you move on, you will often find an answer in a further question, manage your time, I always recommend 1 hour max on the first 20

 

[jreid67]

here it is again

Thank you

 

[trebor]

you are welcome, here`s a couple question about IP that could turn up, in exam language as well and a couple of others for luck

1. Briefly explain the purpose of IP codes 3 marks

2. Explain the difference between IP and external influences 3 marks

3. what are the two correction figures contained within the `rule of thumb 0.8`3 marks

4. when using the adiabatic equation what would the max fault current be for a class 3 CB 1 mark

5. What is the max Zs for a type D 20A CB, show calculations 4 marks

 

[dingo5]

Answers for above?

 

[trebor]

you are welcome, here`s a couple question about IP that could turn up, in exam language as well and a couple of others for luck

1. Briefly explain the purpose of IP codes 3 marks
to enable the specification,selection and purchase of equipment internationally with the same standards of ingress protection

2. Explain the difference between IP and external influences 3 marks
external influences are conditions which can affect an installation whereas IP is a means of protection against the said conditions
3. what are the two correction figures contained within the `rule of thumb 0.8`3 marks
1.20 for correction to 70 deg c conductor temperature and 1.04 for correction of ambient temperature to 30 deg c

4. when using the adiabatic equation what would the max fault current be for a class 3 CB 1 mark
3000 amps

5. What is the max Zs for a type D 20A CB, show calculations 4 marks

Ia for a type D cb is x 20 In

20x20 = 400A

R = V/I = 230/400 = 0.57

0.57 x 0.8 for temp correction = 0.45ohms

Max Zs = 0.45ohms

 

[kenny5522]

anyone got the right answer to these questions list the first four relevant tests, in sequence, to be conducted on the new lighting installation [ 7 marks ]
all relevant test equipment need for the above. [8 marks] have an idea but no sure because of the marks awarded.

 

[mattmoo1974]

Kingston
Short answer questions<<<<<<<<<< The give away is in the name. Dont waffle These are 3 or 4 word answers normaly.
When i did mine i put a legend at the top ie IRT= Insulation resistence tester LROM= Low resistence Ohm Meter
Trust me when i say this will save you alot of writing. It must be ok cos i passed
Oh and if any 1 whats past papers email me at [email protected] and i ll send you a load on.
Hope this Helps

 

[kenny5522]

thanks for the offer but sitting 2391 tonight if i fail i will take you up on it hope i get lucky with the papers tonight

 

[russty]

Does anybody agree with my answers for dec 2010 2391 first 20 only pdf att

Have you had chance to attempt the other 20 at all yet.
From going over the first 20, making me think i must of bombed out on the Dec 10 exam.

 

[kenny5522]

did them all didnt do very well on them but been studying non stop looked at where i went wrong mainly not rtfq.propely.

 

[miner69er]

good luck with the exam tonight people..... i'm taking the 2391 tonight as well in about 4 hours time thats why i'm on the pc relaxing now. if i don't know it now, i never will in the next 4 hours!!!

 

[kenny5522]

good luck as well another 15 min i will knock it on the head.

 

[john25]

Good luck people im booked on the 10th March Exam. as other people have said the Exam Success book really does help and knowing GN3 inside out

 

[SafetyFirst]

Has anyone accidently mistakenly inadvertantly smuggled last nights question booklet out by any chance???

 

[miner69er]

sorry no exam paper....
But a couple of questions last night were:

draw the complete earth fault loop path for a tns system including all the notes/descriptions. (15 marks) get that one stamped in your head as it's a common one!

work out the parrallel resistance of a set of 8 or 9 IR readings

one nasty one was being asked to work out circuit resistance (r1+r2) of a light circuit in 1mm line and cpc, but all that was given was circuit length of 50metres . on the next page was resistance readings per metre for 1.5, 2.5, 4, 6 and 10mm cable..... not 1.0mm!!!!
so the only thing i could think of was to multiply the 10mm resistance by 10 to get resistance for 1mm.

usual questions of what meter for what test

the test papers in the exam success really do give you good preperation