2381 Ask questions and find answers to many subjects relating to electrics and electrical work

[murphy]

Hi all.
Just signed myself up to do the 17th edition wiring regs in a few weeks time (The full 3 day course). I have been reading the big red book and have a few questions i hope some of you experienced guys or girls could help me with.
Here goes.
Is a design current (Ib) the current before or after diversity?
For example i was trying to calculate the voltage drop of my own lighting circuit basing the Ib on 10 fitting, each with a max of 100 watts. So thats 1000 watts divided by 230 =4.34 amps. Do i now apply diversity of 66% for a lighting circuit?
Also, Have max permitted voltage drop figures changed. Its seems lighting is 3% and everything else is 5%.I seem to think it used to be 4% for every circuit.

Still got few weeks before course so will proberbly be on again!

Thanks
murphy

[ericmark]

When you have done the course you can tell us when we are getting it wrong.
All too new yet. Still have not got my copy. The 16th Edition did not have diversity tables these were in 15th Edition it was only the guide to the 16th Edition which had the tables. 15th Edition was 75% for lighting. But there were no such things as GU10 bulbs as since they have a max of 75 watt and hard to find anything over 50 watt seems a little daft to allow 100 watts per lamp? Also max mcb sizes did not include GU10 only SES etc. So I am looking forward to seeing what is included. How long it will take for City & Guilds to catch up is another thing I know when I took the BS7671:2001 they were still asking questions related to BS7671:1992 and unless it has City & Guilds on the bit of paper you may as well bin it. On college here did their own exam and around the area was accepted but once one traveled around the country it was useless.

[kbrownie]

Hi murphy;
The Ib is before diversity is applied,
not heared anything regarding Vd being changed it used to 4% as you stated.
I have no doubt that someone will correct me if i'm wrong, in the mean time i'll open the big red book! that arrived to day and do some searching.
Regards
KB

[sparx]

Hi Murphy, not yet got a copy of 'Red book' but do know from recent seminars that there are now different % figures, also as all calcs now based on 230V [not 240v as in brown book] all max loop impedances have been reduced for overcurrent devices so all those useful crib sheets are now over optomistic.
As for design current figures I always apply diversity first as with say a cooker, as otherwise if you do it at 100% and it goes just over you then apply diversity and its just under it feels like you are 'fiddleing' the figures!
Anyway you still have to apply diversity before working out voltdrops so I don't see it really matters which way you do it, the results the same, I am taking C&G in mid Feb. so will be reading up myself as soon as book arrives, apparantly ECA are sending free copies with a guide book, & I will get one as part of course so could have 2 copies then! would trade both for 1 copy right now!!!
good luck,
SPARX

[murphy]

Thanks for the replies everyone.
Whilst on, i might as well pick your brains again.
Basically, as i stated earlier in this thread, im doing the full course (Not the update) and have not got a clue what to revise. Is there likely to be any maths or is it just regulations. All i Know is that its a 2 hour multiple choise exam.
Cheers
Murphy

[ericmark]

The old course and test was how to read a book. If you can answer some questions without the book, it will increase speed. Highlighting sections likely to be used a lot, will increase speed. Knowing what section to look in will increase speed. But there were also as many questions on Guide to 16th Edition as to the main book which really were building regulations like height of sockets and switches. The only person I knew who failed did so because his mobile phone rang in his bag and he was disqualified. The C&G 2391 was a real exam but 16th edition was not what I would look at as a real test. Tick the box so even if you know nothing 25% and we would use examination skills. Answer those you know. Then answer easy ones, Then start on hard ones, 2 mins from end tick C on all unanswered. Or any other selected letter.
I don’t remember any calculations although it may have asked can 20mm conduit have 5, 10, 20, or 30 times 2.5mm cables when it has 2 bends etc. Which I suppose you could calculate but most just look up on tables. The old books always had a line next to any text that had changed. And although the papers were not to leave to exam some how instructors always seemed to have loads of example questions. Seems that about 10 times the questions asked on any paper were written and random selection was taken for each group so there was a good chance you had seen the exact question before. When we changed editions there was a concentration on questions on changed parts of the regulations so for example they were to change volt drop permitted from 4% to 3% then very likely a question on this. So if like old system look for lines showing changes.

[ericmark]

I though I would bite the bullet and take the course and exam. It has gone from £70 in 2002 to £175 today for special short course for those already with 16th Edition. But also seems there has been a delay in getting the syllabus so has not started yet. Just as well since there also seems to be a delay in getting books. 10 weeks night class. Would be 12 if you didn’t have 16th Edition doesn’t seem much change. With all the changes the web site lists I would think maybe harder for those of us that have to unlearn bits? I wonder how the price varies around the country? I am in North Wales near the boarder 12 miles from Chester.

[kbrownie]

Hi,
Where I live in Bradford, they are bit slow of the mark. closest college currently advertising the 17th edition qualification is Huddersfield it's a three day cousre over three weeks, no price details as yet!
A place in Rotherham charging £475 + vat and that's over 4 days.

It's a 2 hour gola exam with 60 questions.
KB

[sparx]

Hi guys,
I am taking a 3 day course/exam next week but don't have book yet!
NAPIT charging £481
Had tried to do 1 day, but as my 16th cert before 2001, C&G won't allow it!
I was booked on 1 dayer 12th Feb. tried to change it to 3 Dayer & was told next available course JUNE 16-19th, as daughter getting married 21st June decided no-go but would accept a cancellation, today got call for vacancy on Monday, just 1 hour after requesting!!!
Normally would be pleased, but not much 'mugging-up' time!
NAPIT towers here I come, only 4 hour drive.... hey-ho...
good luck everybody taking updates, thankfully I should be retired by the time next one due!
regards SPARX

[ericmark]

I noted it's now the 3282 and there is also a 3292 so seems we have two courses and exams to take. Not sure about the Inspection and testing of in service electrical equipment (PAT testing) will we also have to take those two exams as well? Maybe I should just retire now!

[ericmark]

Just got 17th Edition now it seems I have to become an auto spark? And thats changed what happened to air warning? It have become a rear fog lamp? And all numbers what happened to 54L etc. I think it's time I retired! Well course starts Tuesday 5 weeks night class at 2 hours a go so 10 hours cost £175. And taught by a 70 year old plus ex-teacher. Oh well.

[sbelectrical]

Hi eric i rang the niceic today to see whats what about what courses to
take, here we go; ther are two 17th edition C+G 2382-10 AND 2382-20
THE 2382-10 is to be taken if you do not have the 16th or took the 16th
before 2001 which means you would have the C+G 2380. Now if you
have the C+G 2381 16th regs you can take the update course 2382-20 or
just sit the exam the differance is a 4 day course in the region of £400-
£500 for the 2382-10 or a 1 day course costing £150 to £200 for the
2382-20. As for the testing and inspecting the old 2391 they say we do
not need to upgrade to the 2392 as the way we test is not changing just
some of the readings/results will be affected and doing the 17th course
should be efficiant plus pat testing will stay the same. To sum things up then no need to go and do the test and inspcetion again, if you have the old 16th your on the full 17th if you have the newer 16th youre on the update course luckly im on the update yey. if you go on the niceic web site
and click on courses its all there .

SB

[ericmark]

It is going to take some careful reading. I took ages to find the new volt drop bit I was not looking in Appendix 12.

Some things I have done for years are now stopped. Like fitting 4amp/hour batteries in caravans. It was done to stop ripple to lights but seems 40amp/hour is smallest I can fit now and if to last 5 years will have to be traction no more fitting of car batteries.

I keep making mistakes reading a bit and not realizing it is limited to a special location but I am sure I will get there in the end.

Glad I have not got to do 2392 etc. as well. I seem to spend so much time in school.