Tutorials

[Sidewinder]

Just kyboshed that mate, it is now gonna be a big booklet I think!!!

 

[AusDave]

how are things progressing? I cant wait to see this

 

[Sidewinder]

AusDave,

There is just so much to do and not enough time to do it!

Both Manator & myself are working away quite a bit, and we are also involved with sales work & reporting which takes up a lot of time.

KME has been quiet work wise recently but very busy in other areas.

So all in all probably a while!!!

Sorry all.

 

[kme]

We WILL get there...................Bit like British Rail (if you`re old enough to remember `em!!)

 

[Manator]

Firstly I must apologise for the delay, my intention was to do a concise tutorial, however, when myself Sidewinder and KME got together on this project we very quickly accumulated over 400 pages of information and photographs. The problem we have is what to include and what to discard, as Sidewinder has said we have been very busy, my new job involves working all over the UK, and most of my nights are taken writing reports, which are time critical, and very labour intensive.

I do promise we will complete this little project, but it may be more detailed than originally planned.

 

[apprentice87]

Hey all, No worries.....ALL good things are worth waiting for... and stuff composed by you lot will be MUCH MUCH more than good..... You should make all this into a book and sell the things...I for one would be at the very front of the queue.. the accumulated knowledge of you lot would be priceless.......

Cannot wait......

john

 

[kme]

Thats a scoob for you, then

 

[Technician]

I like this idea. I train my guys to anticipate, by design and measurement, what sort of reads they should expect. I do worked examples using table 9A OSG page 166 and apply limits of accuracy that might apply to a typical instrument so that they can work out what sort of read they should see as a maximum or minimum. I also use my own private records and show how, by investigation and repair, (R1 + R2) values can be reduced.

No two installations are ever alike and this would assist as a body of ready reference.

 

[Technician]

Had a look at some of those shots....gruesomely instructive. Incidentally, I have some VIR which I pulled out of an installation; it is in perfect condition...for the simple reason it has done nothing but power a light since it was installed in 1945.

 

[Nicky Tesla]

What i have found is that books including the part p doctor book, do not discuss the hassles you have to get round sometimes when testing for say r1 + r2 and insulation testing when rcds and rcbos are involved.

Another thing is i love to find other peoples test certs and have a look through them. It is surprising just how many electricians do not have a clue how to do a test cert.

What i often see are;

R1+R2 readings higher than the Zs

R1+R2 readings on a ring higher than the continuity readings

Incorrect max BS7671 Zs figures.....just the other day someone had filled them out for 3871 type 1 breakers when they where all type 2

RCD readings all filled out for a 30mA RCD even though the RCD is 100mA

Insulation test readings.....a lot of people simply dont bother testing these and for a periodic were all is tested at once they will simply put down >299M

Now i have done a lot of testing and these types of figures are rare. Just today I got 43M L/E + N/E & 91M L/N. I have seen a cert with everything

down as >1000M

Ticks for earth rod tested on a TNCS

Ticks for SELV when there isnt any

Ticks rcds present when there isn't any

The list is endless......and has anybody actually seen a chart or diagram for a domestic house electrics, no , so why is that always ticked?

 

[Zeespark]

A chart can be your schedule of circuit results.

AndyGuinness

 

[NozSpark]

Not only have I seen the RCD box ticked when there wasn't one,,, the "Clown" had also completed the trip times boxes on the schedule of tests...... It wasn't as if it was only a PIR,, he'd replaced the CU himself - it should have been done to the 17th edition BTW:O

 

[Voltimax]

What i have found is that books including the part p doctor book, do not discuss the hassles you have to get round sometimes when testing for say r1 + r2 and insulation testing when rcds and rcbos are involved.Another thing is i love to find other peoples test certs and have a look through them. It is surprising just how many electricians do not have a clue how to do a test cert.

What i often see are;

R1+R2 readings higher than the Zs

That is quite possible, bearing in mind that when you Zs test you have all the parallel paths in place.

 

[Andy™]

That is quite possible, bearing in mind that when you Zs test you have all the parallel paths in place.

+1. very easy to get a Zs lower than R1R2

 

[Nicky Tesla]

That is quite possible, bearing in mind that when you Zs test you have all the parallel paths in place.

Stop talking rubbish.........It seems to be a stock answer for anything even slightly technical..........parallel paths indeed ???

From the DB to a cooker point where are the parallel paths?

From the DB to a ring cct with nothing connected, where are the parallel paths?

There arn't any

One place you will find them is to a connection to an immersion, so just temporarily disconnect the earth at the switch.

---------- Post Auto-Merged at 22:02 ---------- Previous post was made at 21:56 ----------

A chart can be your schedule of circuit results.AndyGuinness

You are the one doing the periodic........The chart/diagrams should be there before you write them.

How many domestic periodics have you been to were the schedule is right there next to the DB hanging up in a little plastic sleeve with a ribbon tied to it mmmmmm never!!!

 

[Andy™]

your the only one talking rubbish Nicky.

and Zs is a live test with all bonding in place. you do not disconnect an earth to do the test, as you have described.

and if you still cant figure out how a parallel path will be on many circuits, i suggest you go become a plumber.

 

[Zeespark]

I was looking at it from the POV of the new schedule that has been written as being the chart.

AndyGuinness

 

[Sidewinder]

testing for say r1 + r2 and insulation testing when rcds and rcbos are involved.

What is the issue in obtaining r1 & r2 when an RCBO or RCD is involved.

I fail to see what an RCBO or RCD has to do with taking an r1 & r2 reading.

This could well be an issue as it is not covered in the 2391 course notes or tutors guidance or examiners marking information for the 2391-10 course.

Can you please explain in detail, as none of my students today had trouble explaining how to do these tests after we had covered it in the course, nor did they have much trouble in taking the readings on the examination board.

Sorry, please note that the r1 & r2 above should have subscript numerics, but I can't get this to display correctly on the forum.

 

[Nicky Tesla]

Come on then explain.....your cooker cct has no cooker attached it is not connected to anything from the DB all the way to the outlet....where are the parallel paths?

 

[Sidewinder]

Herr Tesla,

As has just been explained to you if you have not grasped this fundamental issue then please find another career.

This is something you should know & fully understand if you are competent to test and have passed the 2391-10 (or its predecessor courses).