Re:Re: Electrician's Qualifications.

Could anyone suggest the names of any text? books / media, an aspiring (and perspiring) wannabee trainee 'Lectrician might obtain to learn such secrets as; Cable calculations? Or any of the other "black" arts the NICEC or IEE, deem crucial in awarding the coveted "competency accreditation" to? ;0)

TIA.

Reply to
RmS
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Starting a new thread is good, but maybe you could have given it a new title too :-)

Books depend on your current level of understanding.

For "how it is normally done", one of the Collins books is pretty good (DIY wiring and lighting), but contains next to no technical background.

Reading the last five years of electrical questions on uk.d-i-y would be a good start too, and there's a bit of info in the FAQ :-)

Far too much technical background is available from John Whitfield's "The Electrician's Guide to the 16th Edition of the IEE Wiring Regulations", and some of his advice conflicts with that in the IEE's official guide, the "On-site Guide". Nevertheless, Whitfield is still many electricians' "bible".

The OSG itself is a brilliant source of practical advice for most (single-phase) work, though biased towards domestic, fully referenced to BS7671 and very easy to read.

There's also a lot of information in BS7671 itself, which you're probably going to need anyway, but it can be a little difficult to extract. A really good way to get the hang of BS7671 and the OSG is to take a C&G 2381 course. When I did mine it was a few months of one-evening-a-week in college, followed by an exam.

The exam questions are copyright City & Guilds, so example questions are a little hard to come by. A clever Google on this group though might throw up something interesting.

I also have two books by Brian Scaddan; "IEE Wiring Regulations Explained and Illustrated" and... errr... something to do with testing. These are much easier to read and understand than Whitfield's book.

As for criteria for membership of (e.g.) NICEIC, try the respective websites:

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M.

Reply to
Martin Angove

ISTR I culled a set of example questions from somewhere onece... not sure how representertive they are but they seem like the sort fo thing I would expect to find...

I can dig em out and post them if you want...

Reply to
John Rumm

Hi, and thanks for the comprehensive information. I would indeed be most eager to get hold of some "Test" questions - Thanks. - And i will certainly try to get the OSG.

Thanks again.

John - just remove the obvious from the reply address.

Reply to
RmS

(these may have suffered a bit from being cut and pasted... note read Ohms where you see "W". Answers in brackets at the end)

  1. A single-phase circuit is to be wired in 70°C PVC-insulated and sheathed multicore cable to BS6004 with copper conductors. The cables are to be installed single in conduit without insulation. The nominal design current of the circuit is 30A, ambient temperature is 50°C. If a BS88 gG fuse of rating 32A has been selected, determine the minimum cross sectional area of these cables that can be used. [10mm2]
  2. A single-phase circuit has a nominal design current of 17A and a BS3036 semi-enclosed rewireable fuse of 20A rating has been selected. Ambient temperature is 45°C and the cable is installed with 4 similar cables all clipped direct. BS6004 70°C PVC-insulated and sheathed multicore cables are employed. Determine the minimum cross sectional area of the cable to be used. [10mm2]
  3. Six similar single-phase circuits, each designed for 8A and protected by a 10A miniature circuit breaker are wired in BS6004 70 °C PVC-insulated and sheathed copper multicore cable. The cables operate at an ambient temperature of 45°C and are totally enclosed in thermal insulation with a derating factor of 0.5. Determine an appropriate cross sectional area for the conductor. [6mm2]
  4. A single-phase a.c. circuit is wired in single core 70°C PVC-insulated non-sheathed cable to BS6004 having copper conductors of
10mm2 cross sectional area in conduit (CR1). If the nominal design current is 40A and cable length 33m what voltage drop is experienced down the cable? [5.8V]
  1. A 240V single-phase a.c. circuit is wired in multicore 70°C PVC-insulated and sheathed cable to BS6004 with copper conductors. The circuit length is 20m with a design current of 25A. The cross sectional area of the cable is 6mm2. The circuit is taken from a distribution board supplied with 240V single-phase cable, again to BS6004 with cross sectional area 25mm2 and design current 100A over length 30m. All cables are clipped direct. Determine the voltage at the point of utilisation. [231.1V]
  2. Eight similar single-phase circuits are grouped together, clipped-direct, each having a nominal design current of 24A and protected by a 30A BS3036 semi-enclosed, rewireable fuse. The circuits are run in 70°C PVC-insulated multicore, sheathed cables to BS6004. If ambient temperature is 30°C and the cable run is 70m what is the minimum cross sectional area that can be used and what is the voltage drop? [16 mm2, 4.7V]
  3. A single-phase circuit is run in single core 70°C PVC-insulated and sheathed cable clipped-direct and not bundled with other circuits. The conductors are copper with a cross sectional area for the line conductor of 4mm2 and protective conductor of 2.5mm2. The length of the cable run is 45m and Ze=0.35W. Assuming an earth fault at the load with a loop impedance for the cable of 16mW/m calculate the earth fault loop impedance and the fault current that would flow with a 240V supply. [1.07W, 224.3A]
  4. In an installation which is part of a TN-C-S system a final circuit is fed from a sub-distribution board. The distribution circuit from the main board to the sub-distribution board is run in single-core 70°C PVC-insulated cables having copper conductors. The live conductors being
25mm2 and protective conductor 16mm2 and a loop impedance of 2.59mW/m. the distance between the distribution boards is 27m. The final circuit is run in 6mm2 twin conductor with CPC with a loop impedance of 14.48 mW/m and length 22m. If Ze= 0.35W calculate the earth fault loop impedance, a) at the sub-distribution board, b) at the final circuit board. [0.42W, 0.74W]
  1. A 240V single-phase circuit is run in BS6004 multicore cable with main conductors of 16mm2 and protective conductor of 6mm2 and loop impedance of 5.84 mW/m. the cable has a length of 40m, operates in an ambient temperature of 30°C and has Ze=0.35W. Use the adiabatic equation with K=115 to calculate the maximum disconnection time allowable for a protective fuse. [2.8s]
  2. A 240V single-phase circuit is run in 6mm2 two core with a 2.5mm2 CPC for a length of 35m. The cable has an earth loop impedance of 14.48 mW/m and Ze=0.35W. The circuit is protected by a 40A MCB (type B) which offers a disconnection time of 0.1s. Check that the adiabatic equation condition is satisfied if K=115. [784 Thanks. - And i will certainly try to get the OSG.

One of the cheaper sources:

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Reply to
John Rumm

Ok, I was being a bit obtuse. Try

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put these up in 2003 when I took my 2381.

Hwyl!

M.

Reply to
Martin Angove

Ah, ok see what you mean... ;-)

Some questions about your questions:

Have you get the answer sheet for the tail last few questions that are missing answers? (I want to check my score! ;-)

What exam conditions are these taken in (i.e. open book / closed book / with data sheet handouts etc?)

How many other papers are there? And what form do they take?

What is the required pass mark? (I take it there is just a pass/fail result and not some sort of grading...)

Reply to
John Rumm

Errr... yes, I do have the answers knocking about somewhere. I'll try to post them later.

It's explained on the index page. Basically, open book (BS7671 & OSG) calculator allowed (though you shouldn't need one). Note that my exam was taken during the last issue of BS7671 (blue book) and therefore page references may be different, and I suspect that there have been some new questions added to do with harmonised colours etc.

The paper I copied those questions from was handed out by our lecturer as practice. It wasn't in exactly the same format as the "real thing" so had obviously been laid-out by him (or his secretary), but some of the questions were so close to the ones on the actual paper that he must have copied them down. In the exam, answers were marked on a separate machine-readable sheet and the question papers were collected in at the end and counted. We had three or four practice papers, but I don't have the time any more to put that sort of thing on the website.

I guess that they re-use questions and given that there are probably at least two opportunities per year to take this exam, and 60 questions needed per paper, the last thing they want is six or seven "real" papers "in the wild" as they'll likely as not contain all possible questions!

Can't remember off hand. It was more than 50% FWIR, 65%? 70%?

Hwyl!

M.

Reply to
Martin Angove

Sorry, should have read that bit.. ;-)

I think I have dropped about three or questions so far (including the Earth Fault Loop impedance one that made no sense) without using any books... Admitedly a couple of answers were educated guesses though (never had much cause to look up details for saunas!). So with the OSG to hand that ought to make it pretty stright forward then I would guess....

Yup, sorry me not being clear enough again... I was talking about the "real thing" rather than the example.

The example you posted was a multiple choice paper, I was wondering if the whole exam is like that, or whether there were more detailed writen papers that followed (i.e. like exams when I were a lad).

Do you still have to fill em out in an a HB Pencil? ;-)

I think that is true of most exam papers. IIRC when I took my A levels for things like computer science and physics there was perhaps a cache of 60 questions for the papers of which 18 or so would make it into each paper. So if you had a set of past papers you would have examples of most types of questions even if the fine datail and the numbers would change. IIRC they did a bigger change of questions each five years or so to keep people on their toes. Probably not as easy when you want to test knowedge and understanding of a particular set of documents though.

Reply to
John Rumm

We all do it :-)

It's better that way, so long as you are absolutely sure of yourself. At two hours and 60 questions it averages (obviously) two minutes per question. Any that you can do more quickly will gain you time for the tricky ones.

No, for the 2381 that's it. One paper, multiple choice, 60 questions. Unless things have changed since I did it. The 2391 is a lot more effort, and includes a practical test.

I think they're OCR'ed, but yes, the advice was pencil IIRC. If they really do OCR them then anything black should do, though pencil at least gives you the opportunity to change your mind :-)

Reminds me of Dirk Gently's Holistic Detective Agency - Svlad Czelli (or whoever he was before he became Dirk Gently) went through all the past papers in his University's library and came up with a set of "most likely" questions and was thrown out for cheating because he got them exactly right :-)

Back to the thing I put up (in June 2003 from the filedates) it turns out that I had actually prepared all the answers but hadn't got around to uploading them! I have now done so. Have fun.

Hwyl!

M.

Reply to
Martin Angove

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