what tests are you doing on consumer unit change.

[daz1963]

Hi all. when changing a consumer unit,what tests are you doing for eic?continuity of ring and bonds,insulation resistance,polarity,zs and rcd tests. or are you doing R1+R2 as well? i normally do the R1+R2 tests as well but takes extra time and is it really nessesary? on the ring mains i can understand the end to end, i,ve seen a few forums where some peeps are testing Zs but not R1+R2. i can,t find anything that says otherwise so not really sure whats right and whats wrong. any advice would be very welcome.
Regards Daz.

 

[Sparky Ninja]

Measuring R1&R2 or R2 is an absolute necessity on a consumer unit change.

Measuring Zs and obtaining R1&R2 from the measured value is cowboys work.


Make sure you fully understand the purpose of carrying out these individual tests then you should realise why they are essential.

 

[spark 68]

Hi,

I couldn't say what is right or wrong, but I usually test and record the lot, as there is rarely, if ever, prior paperwork.

I don't do a 'formal' EICR before hand, but still do a quick pre-test, how much depends on the condition of the installation, but I don't record this other than maybe the Ze and PFC which would go on the EIC, unless I need to change something that would affect this, ie. Earthing conductor or new rod, Main bonding or tails.

 

[Amp David]

I always find the titles of the columns on a schedule of results is a give away as regard what test are required. hone:

 

[Octopus]

Hi all. when changing a consumer unit,what tests are you doing for eic?continuity of ring and bonds,insulation resistance,polarity,zs and rcd tests. or are you doing R1+R2 as well? i normally do the R1+R2 tests as well but takes extra time and is it really nessesary?

Absolutely scarey.

If it takes extra time are you allowing sufficient time to do the job correctly? Cutting corners isn't the way forward.

 

[Mark_Burgess]

READ THIS THREAD http://www.electriciansforums.net/e...ctrical-regulations/12971-cu-changes-you.html

 

[daz1963]

who said anything about cutting corners. read my post again and you will see i test R1+R2. what i said was some people on this forum and other forums don,t. if you do a forum search on here you will see for yourself. but as i understand it R1+R2 is a dead test to verify a circuit is safe to energise and would meet disconnection times, Zs is is the live test what will also give you a value to ensure disconnection times are met. if you have a Zs reading and a Ze reading why do R1+R2? surely that should be enough. on a ring final yes to find any cross connections, or a full rewire.but on a previously installed radial? thats already been energised before it was switched off before commencing a cu change. correct me if i'm missing something here.
regards daz.

 

[pencilpusher]

Daz, I think he is referring to this comment "i normally do the R1+R2 tests as well but takes extra time" It comes across as a time issue TBH. Do all the tests. You are changing the nature of all the circuits by changing the CU. I treat that as a new install when testing. Safety first 'cos it has my (your) name on the EIC!

 

[daz1963]

Sorry. it does sound a bit that way. i never seem to be able to type what i want to say.
regards daz.

 

[roukel01]

Well, RCD's are installed nowadays so no need to do insulation resistance test, cos yer RCD won't set if there's a problem. Then a couple of Zs tests here and there to make sure you've got an earth.

The rest of the testing is carried out at home. :behead:

 

[brman]

Sorry. it does sound a bit that way. i never seem to be able to type what i want to say.regards daz.

I got what you meant!

sounded like a reasonable question to me - what do you get from an R1+R2 on a radial circuit that you don't get from a Zs?
If the answer is that you need the dead test 1st to check it is safe before energising then you can just do it before you isolate the installation before the CU change.

Personally I don't do a Zs measurement on radial circuits if I can help it. I use Ze+(R1+R2). Particularly on lighting circuits I don't like removing roses etc to get to the earth when the cct is live.

 

[plugsandsparks]

I like ZS tests cos after all the unscrewing and screwing of terminals i can test it last when its all done, gives me a warm comfy feeling i have left it all good.

 

[SirKit Breaker]

I like the new model EICR forms, and the generic test result schedule, takes away all the guess work as to what tests you should do, and it even has a tick box for operating the RCD test button.

Cheers...........Howard

 

[Des 56]

This is the ESC advise
10.2. In addition, as a minimum, the following testsshould be carried out to the existing circuits
connected to the replacement consumer unit.
• A continuity test of the protective conductor of
each circuit, to the point or accessory electrically
furthest from the consumer unit and to each
accessible exposed-conductive-part.
• A continuity test of all ring final circuit
conductors.
• A measurement of the combined insulation
resistance of all the circuits. The measurement
need only be made between the line and neutral
conductors connected together and the
protective conductor connected to the earthing
arrangement.
• A test of the polarity and a test to establish the
earth fault loop impedance (Zs
), at each
accessible socket-outlet and at least one point or
accessory in every other circuit, preferably the
point or accessory electrically furthest from the
consumer unit.



Note
R1+R2 values are not mentioned
Here is a link if you want to refer to their bumph
http://www.esc.org.uk/fileadmin/user_upload/documents/industry/best_practice/BPG6_09.pdf

 

[jase]

I got what you meant!

sounded like a reasonable question to me - what do you get from an R1+R2 on a radial circuit that you don't get from a Zs? Tell you what you dont get- parrallel paths
If the answer is that you need the dead test 1st to check it is safe before energising then you can just do it before you isolate the installation before the CU change.

Personally I don't do a Zs measurement on radial circuits if I can help it. I use Ze+(R1+R2). Particularly on lighting circuits I don't like removing roses etc to get to the earth when the cct is live.[/QUOzTE]

On initial verification there is no need to measure Zs, as this would have been measured by Ze + R1+R2, but on a periodical it is exceptable to measure Zs as the circuit is already energised, and write lim or NV in the R1+R2 box on the cert, on a fuse board change there is no reason not to measure Ze and R1+R2 as the installation will be de-energised anyway

 

[jumpin jax]

For domestic i think a real time saver is to get a R2 lead, this also allows quick cpc testing at every point. Just make sure there are no painters or plasterers on site or the lead won't last too long!

 

[Engineer54]

Well, RCD's are installed nowadays so no need to do insulation resistance test, cos yer RCD won't set if there's a problem. Then a couple of Zs tests here and there to make sure you've got an earth.

The rest of the testing is carried out at home. :behead:

You should always be conducting tests ''Prior'' to any CU change!!

Errr, ... there are normally no RCD's in the CU ''Before'' changing the CU, ....But there is AFTER!! ...IR testing is essential, Pre a CU change. You may not be able to get either RCD to hold in after your CU change if the insulation levels are too low!!!

Even after a CU change, and even if the RCDs are holding in, IR testing should be carried out as a matter of course, it's a record against which any future EICR can be compared. Which in essence, is one of the fundamental reasons of EICR's in the first place, ...monitoring any deterioration of the installation!!....

 

[Sparky Ninja]

This is the ESC advise
10.2. In addition, as a minimum, the following testsshould be carried out to the existing circuits
connected to the replacement consumer unit.
• A continuity test of the protective conductor of
each circuit, to the point or accessory electrically
furthest from the consumer unit and to each
accessible exposed-conductive-part.
• A continuity test of all ring final circuit
conductors.


Note
R1+R2 values are not mentioned
Here is a link if you want to refer to their bumph
http://www.esc.org.uk/fileadmin/user_upload/documents/industry/best_practice/BPG6_09.pdf

Naturally R1&R2 or R2 would be required for the first test mentioned.

 

[roukel01]

You should always be conducting tests ''Prior'' to any CU change!!

Errr, ... there are normally no RCD's in the CU ''Before'' changing the CU, ....But there is AFTER!! ...IR testing is essential, Pre a CU change. You may not be able to get either RCD to hold in after your CU change if the insulation levels are too low!!!

Even after a CU change, and even if the RCDs are holding in, IR testing should be carried out as a matter of course, it's a record against which any future EICR can be compared. Which in essence, is one of the fundamental reasons of EICR's in the first place, ...monitoring any deterioration of the installation!!....

Sorry, I thought that by putting the little picture on the end, you would realise it was ment as a joke.

 

[Engineer54]

Sorry, I thought that by putting the little picture on the end, you would realise it was ment as a joke.

Sorry, .....Probably just me not noticing..lol!! Been busy reviewing drawings and writing them up tonight!!
So only popping on here in between and coffee/smoke breaks...lol!!

Time for bed now i think, my eye's are tired...:yawn: lol!!!

 

[Des 56]

Naturally R1&R2 or R2 would be required for the first test mentioned.

Naturally and agreed,its one or the other required


The listed test procedure was in response to the first post

quote
i normally do the R1+R2 tests as well but takes extra time and is it really nessesary

The test procedure was pasted and the required Zs test was highlighted
I included a note that R1+R2 values were not mentioned with regard that question
Des

 

[Deleted member 9648]

You should always be conducting tests ''Prior'' to any CU change!!

Errr, ... there are normally no RCD's in the CU ''Before'' changing the CU, ....But there is AFTER!! ...IR testing is essential, Pre a CU change. You may not be able to get either RCD to hold in after your CU change if the insulation levels are too low!!!

Even after a CU change, and even if the RCDs are holding in, IR testing should be carried out as a matter of course, it's a record against which any future EICR can be compared. Which in essence, is one of the fundamental reasons of EICR's in the first place, ...monitoring any deterioration of the installation!!....

The 'real world' problem with tests prior to a CU change is more often than not you are asked to quote for the job. So you go round and carry out a full set of tests which takes time...and then dont get the job....sod that.
When we quote for a CU change a visual inspection is usually sufficient to get a feel for the likelyhood of any issues,and our quote clearly states that any problems encountered during the CU change may incur extra cost. Testing and inspection is then carried out at the time of the change. I am an experienced fault finder and cant recall any issue which added more than a couple of hours to a job. I've done hundreds of cu changes and there have never been any customer problems with this approach.
This might not be a text book approach,but there are no ideal solutions here....a text book approach is liable to result in me carrying out a pir for nothing....and I aint doing that.
Those who cant trace faults may prefer not to adopt this way of doing things.

 

[ezzzekiel]

i agree with him above :iagree:

 

[roukel01]

Same here, its how I've always done it.

 

[Engineer54]

The 'real world' problem with tests prior to a CU change is more often than not you are asked to quote for the job. So you go round and carry out a full set of tests which takes time...and then dont get the job....sod that.
When we quote for a CU change a visual inspection is usually sufficient to get a feel for the likelyhood of any issues,and our quote clearly states that any problems encountered during the CU change may incur extra cost. Testing and inspection is then carried out at the time of the change. I am an experienced fault finder and cant recall any issue which added more than a couple of hours to a job. I've done hundreds of cu changes and there have never been any customer problems with this approach.
This might not be a text book approach,but there are no ideal solutions here....a text book approach is liable to result in me carrying out a pir for nothing....and I aint doing that.
Those who cant trace faults may prefer not to adopt this way of doing things.

I think you hit the nail on the head with your last sentence!! lol!! Far too many new electricians out there these days, that are not skilled at fault finding!! Having said that, how long does it take to do a few IR tests, and a quick check for the borrowed neutral syndrome?? I think i'd do these brief tests, just so i'd know where i stand, and what i was in for after the new CU has been installed!!

 

[daz1963]

Thanks to all who responded.

 

[Tuttle]

Personally I don't do a Zs measurement on radial circuits if I can help it. I use Ze+(R1+R2). Particularly on lighting circuits I don't like removing roses etc to get to the earth when the cct is live.

That's what I used to do, in fact that's what I was taught to do, but the chap from ELECSA was not impressed. He said that I had to open up the ceiling rose, do a live Zs measurement and record that on the EIC, not just calculate from the Ze and R1+R2 measurements. Don't know if that was his own personal opinion or the opinion of ELECSA though. I think that he was concerned about the possiblity of the CPC being disconnected from the CU while performing the R1+R2 test and then not getting reconnected properly.

 

[brman]

I was also taught Ze+(R1+R2) is the preferred method as reduces live working and so conforms to EWR 1989. On the other hand I was chatting to my tutor when doing my 2395 practical last night and he agreed that a Zs on the cct was a good idea to ensure you have put everything back together properly. However he was quite happy I didn't do it during my practical as it isn't required by guide note 3.

I have to admit that, after reading this thread and thinking about it a bit more, I will probably do a Zs on radials in the future as long as I can find a safely accessible ceiling rose or whatever. I am not going to lose sleep if I don't though!

btw. Who was the elecsa chap? I have David Turpin turning up tomorrow to do my assessment.

 

[rich.250]

EIC!
As its a new install effecting every cct from that DB.

 

[Tuttle]

Who was the elecsa chap? I have David Turpin turning up tomorrow to do my assessment.

I can't remember his name, but I'm pretty sure it wasn't David Turpin

 

[brman]

I can't remember his name, but I'm pretty sure it wasn't David Turpin

Ok, thanks, we will see what he thinks about it tomorrow as it will be obvious from my certs I haven't been doing a Zs on a radials........

 

[Octopus]

Ok, thanks, we will see what he thinks about it tomorrow as it will be obvious from my certs I haven't been doing a Zs on a radials........

Yes, that will be interesting. Keep us posted.

 

[roukel01]

To be honest, I find it hard to belive folks don't carry out Zs testing. And I certainly would be doing it for my assesment, in fact that was the test I had to carry out for Elecsa this year!

 

[brman]

Well, my Elecsa assessment is done (passed without any problems ) and I asked the guy about this. He confirmed that they like to see a Zs test to back up the dead tests. He did agree though that could be see as contrary to the EWR (minimising live testing) so should only be done if there was safe access to the live circuit.

I too was asked to do a Zs on a radial circuit for the assessment.