2391 question

[la poste]

Greetings all.

I am due to take my 2391 in a few weeks and am revising.

I am a postman so I do not test all day long, the exam is quite a challenge to me.

I have this question that has been puzzling me I wonder if anyone can offer any suggestions:

Here is the question:

"An electrical installation forms part of a 400/230V three phase four wire TN-S system with an earth fault loop impedance of 0.4Ohms.

A new TP&N distribution board fitted with BS EN 60898 type C circuit breakers has been installed for the new lighting circuits.

The new fluorescent luminaires are surface mounted.

The ground floor luminaires are controlled by a photo cell and the remaining luminaires are controlled solely by circuit breakers.

The installation is carried out in multi core steel wire armoured cables with 2.5mm copper conductors, one of the cores of the cable is used as cpc.

Describe in detail how an insulation resistance test would be carried out on one of the completed ground floor lighting circuits.

The car park is to remain operational while the testing takes place."

I understand how to do an insulation resistance test.

I would also include safe isolation procedures and warning signs

checking of leads and batteries etc.

What I am not sure about is if I can disconnect the lights.

Also because the public is using the car park during the test.

Would it be better to:

1. disconnect all lights and photocell, link the disconnected cables together to ensure the circuit remains in tact and test at 500V.

2. Or link line and neutral together and test between them and earth

3. Or some other way

The fact they are fluorescent lights and it may be inconvenient to disconnect them and the fact the public are at large is kind of confusing me.

I wonder if it OK to IR at 500V with the public at large

Can anyone offer any assistance with this?

Thanks.

 

[revjames]

Pardon me for asking, but why are you doing the 2391 if you are a postman?

 

[la poste]

It's my hobby and I hope will earn me some money in my part time.

Maybe even full time one day when the post office finally sinks like the Titanic.

I work with an electrician at the weekends when I can.

House bashing mainly on a Saturday and some wiring on a Sunday.

It's as close as I can get to an apprenticeship.

It's my plan B ray

 

[revjames]

Well to be honest the 2391 is for qualified electricians who do inspection and testing. Apprenticeship and experience of the job would be more use at this stage!

 

[la poste]

Not much chance of getting more experience on the job so might as well do some exams.

Keeps my brain active.

Any particular reason why I should not do this exam?

I mean studying is a good thing right?

 

[revjames]

Nothing wrong with studying. Gaining knowledge is always good. BUT, the 2391 exam is in 2 parts theory and practical. Whilst you might be able to do the theory questions (try some past papers plenty on internet) I doubt you would have the practical skills nor experience neccessary to pass the practical part. Many electricians struggle with the theory and practical parts. Overall success rate is only about 40% Also not sure but I think there are minimum requirements to be able to sit 2391.

Another factor is the costs. Its not a cheap course. You would be better off putting the money towards studying the trade, college etc. Not sure how it works these days and apprenticeships thin on the ground.

Even if you did pass it, without you actually being a qualified spark or the relevant experience would make you "know enough to be dangerous" if you know what I mean.

 

[SPECIAL LOCATION]

I am a bit concerned that if you are due to sit the exam in a few weeks, then by now you should be sufficiently knowledgeable, experienced and competent to answer the sample question unaided...?

City & Guilds own guidance for this course recommends:-

This qualification is intended for experienced personnel working in the electrical industry. AlthoughCity & Guilds does not state formal candidate entry requirements, the qualification is not intended

for non-qualified electricians and/or those who do not have experience in inspecting, testing and

certifying electrical installations.

Candidates without this experience should seriously consider undertaking the City & Guilds Level 2

Certificate in fundamental inspection, testing and initial verification (2392-10) as well as obtaining

industry experience. It is also strongly recommended that candidates have achieved either the City

& Guilds Certificate in the requirements for electrical installations (BS 7671 January 2008) (2382) or

similar qualifications where candidates have demonstrated knowledge and understating of the 17th

edition.

Thats the words of the people who design the course and write the exam. not anyones personal opinion..

I do hope you are not wasting your time and money going outside your depth...

However just as a brief observation after a quick look at the question:-

Your comments about doing L+N to earth @ 500v and worries about public being around...

look at the description of the installtion...

i.e. are we looking at a lot of exposed conductive parts ..

e.g. metal conduit...?

metal light fittings that are WITHIN reach?

metal-clad switches which public may touch?

OR

Is it SWA with a core used as CPC? (insulated and possibly glands covered in shrouds.. )

Light fittings on ceiling above the height that an average car can travel under...

6.5 -7ft high.. Out-of reach maybe?

No switches that Joe public can touch?

ie. circuits controlled by photocell or circuit breakers at board..

etc..

etc..

These IMHO are quite basic observations that any person risk assessing a task in an environment would carry out second nature...

Which you should already be at if you are to get a good pass in 2391..

:coffee :C

 

[Megaohm7]

Hi La Poste. Firstly Well done for trying to put another feather in your cap. I understand that you are keen to learn what you can about the trade. From a personal point of view I won't knock anyone for that, what has been said to you from the other members is in no way meant to put you off but as they have done 2391-10 myself included will say how difficult it is to pass. The theory side of things is possible if you are really switched on to the subject as you can study from GN3 and BS7671 for example. The tricky part comes with the practical as it is a 3ph rig and a sub board with single ph. There is also rigs that you have to fault find too. All this has to be done in a set time. I only really do Domestic myself and im registered with Elecsa but I was lucky enough to know commercial sparks that I could go and do testing with them so I could find my way around a 3ph board. When I did my 2391-10 between Jan-Mar this year, it was all theory and no practical. Only you will know if you are up to it and it's your hard earned cash too. Check out the learning zone on here if you've not already done so. Good luck with whatever you choose to do.

 

[la poste]

I'm only really thinking about the theory at the moment.

The practical can come later even if it means I will re-sit it, you know fail first time.

I think I will be OK with the theory.

There's a lot to learn.

It's keeping me fully occupied.

Thanks.

 

[carshalton]

Well done for trying to better yourself while you work ,snap i was a window cleaner for 20 years and after all that time i decided i wanted a change , so i went to college for 2 years every saturday while still cleaning windows full time , to do my city and guilds in sparks, , the 2391 is blow up all out of size in my eyes, good luck with it , i took mind at crawley after passing just my level 2 in the 2330 after just one year ,i had passed the 17th and pat testing already at redhill college after 6 months, oh i left school at 15 with nothink my the way, not brainy at tool , , 13 of us took the 2391 and 5 of us passed i was one of them who studied my arse off and passed it, the problem is people think because they have been a sparky for a while they will pass it easy ,wrong you can pass this by learing it from a book , not hard i proved it , but there is a way to answer the questions, you will see this if you can get hold of a few sample papers, , and those who had be in the field never studied , big mistake most of them fail , some dam good hands on people to , certilficates mean you known enough to pass the exam end of, not that you can do it in the real world, i finished all my exams in feb and since i have passed C and G in pv solar panels , i went looking for work as a tester first job in the field , lol lol what a wally i was , but i was honest and said i can do it all on paper, thats it , i spent a week with a another tester on the job holding my hand , then after a week they saw i was ok , i was allowed to start my own testing in different flats in the same block , now 6 months on i`m in the field full time and in the real world as i say , i`m testing on a job in cheslea, for the last four months new built flats again , and flying , be honest and good electricans will help you so much in the real world, Alan

 

[Robin Spark]

Hi Poste, have you thought about Pat testing?

its a lot less involved than 2391 and doing inspect & test of installations.

 

[madeinengland]

i'm not in the trade.i started doing my electricians course because the company i work for was going belly up and i needed something to fall back on if and when it finally went under. 6 years later and the company is doing really well. i have never tested outside of the classroom and i have passed everything including 17th edition and the dreaded 2391. anyone who tells you experience is more important is probably right,but don't let that put you off doing the exams. seriously it's tough but not nearly as tough as everyone makes out.

 

[bhamoggy]

I'm very much in the same boat here, I start the 2391 tomorrow evening at Crawley college.

I did 2330 level 2 which took 2 years in the evenings at Worthing and did 2330 level 3 finishing in June.

I've got about 3 months site experience and very little testing experience.

There's next to no jobs down where I live near Brighton unless you're experienced or have the 2391

The course is about

 

[hasan]

I am in the same boat completed my city & guilds level 3 in june and also passed the 17th edition 2382.Starting 2391 next week. only experience i've got is testing at college.But i am going to study hard and give it my all. goodluck to all

 

[bhamoggy]

First lesson was easy, going over gs38 and earth fault loop paths. Nothing new from 2330 level 3

However, he gave us a mock paper, mmmmmmm!!!!!! Well tough!

I can see why the pass Mark is so poor

 

[la poste]

Hi Poste, have you thought about Pat testing? its a lot less involved than 2391 and doing inspect & test of installations.

Well I passed the practical today and the theory three weeks ago.

It's a challenging exam which is good because that's the reason I took it, for the challenge.

What's the point of taking a mickey mouse exam that teaches you nothing?

37% success rate on the theory which means a lot of people failed.

They are changing the 2391 next year apparently to make it easier so I'm lucky I took it when I did.

 

[johninlondon1]

well done & good luck

 

[Sidewinder]

I have been told it is not getting easier also, one of the main triggers for the course change is the fact that the PIR is going!

Also IIRC the 2394 will be a pre-requisite for the 2395 which will be a pre-requisite for the 2396?

 

[batty]

Well done La Postie.