S

Spudnik

Chaps,

After reading several posts, threads etc about CU changes and what you are responsible for, i thought i would clear a few things up for those that are unsure.

Now, this affects anyone changing a CU to bring an installation up the current standard, which of course is BS7671 2008.

Now, the following are RECOMMENDATIONS and not set it stone, but its what i normally try and do, which can save a lot of time and trouble.

If you have been asked to price and change a CU, for whatever reason, you should ALWAYS carry out a site survey before any costs are discussed.

Now, once onsite consider carrying out the following:

1- Main Earth Bonding.

i) Is main earthing present?
ii) If so, is it adequate?
iii) IF not include this in your quote as this MUST be up to current standards.

2 - Visual Inspection

i) How old does the installation look?
ii) Are there broken accessories?
iii) Is there evidence of any additions or alterations, good or bad?
iv) Ask the client of any known issues or problems in the past.

3 - Quick Basic Check & Tests

i) If convenient, isolate supply and take off the CU cover
ii) Evidence of additions or alterations?
iii) Carry out IR test between Earthing bar & Neutral bar at 250V


If everything looks ok then you are good to go, BUT, whatever happens, make sure you draw up some form of basic contract that highlights the fact that the quote does not include putting anything un-forseen right, and that if there are problems found during or after, then they may need to be rectified at additional cost.

Now, if there are issues with an installation that are not considered unsafe, although not to current BS, (unearthed lighting circuits excluded), you ARE NOT generally required to put these right, although they should be noted on the cert in the correct box.

4 - Certification.

There is a little confusion about what cert should be issued, of course, after a PIR is carried out.

The way i do it is, if i do a CU Change a full installation cert is issued, noting any deviations.

On the same cert any circuit additions or alterations can also be noted, so there is no need to write out multiples.

If you are just altering circuits with no CU change, then a separate minor works must be issued for each circuit altered.



Also, once you have changed a CU, carried out all the tests, you DO NOT become responsible for the entire installation - just the CU change.

This must be noted on the cert & periodic inspection label that MUST be fitted after the change with the words - "CU CHANGE ONLY".

Hope that helps, and if there any E&O's then let me know.

Good luck - As most CU changes need it :D
 
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Thanks for that post, really useful in what seems to be a murky area.

Just to confirm .... if I change the protective device on each circuit as per c/u change ..... I'm not legally responsible each circuit? What do you mean by "just the change of c/u"?

Sorry if i'm being a bit pedantic .... just want to be sure.
 
surely if you are re-energsing the circuit after changing the protective device/testing the circuit you must accept responsibility.

I would also say (not that i'm an expert) that when carrying out all of the tests as required, if the test results and visual inspections are all satisfactory, then there should be no reason not to accept responsibility for the installation

as that is what the test and inspection is designed to do??
 
You are not required to carry out a full PIR when changing a CU, although it is wise to do a fairly thorough inspection for any major non compliances.

If you change a PD for a circuit, you DO NOT become responsible for the circuit, only the device thats protecting it. Therefore you must ensure you choose the correct rating and type.

And as you have changed the devices, you must carry out all tests as you must complete a full EIC for the job.

The CU has the PIR label, with "CU CHANGE ONLY" written on it, as this is all you have done, unless this has been part of other works.

** You are ONLY responsible for the work YOU do.**

Although you do have a little responsibility in putting any major problems right, IE broken RFC, etc.
 
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Slightly off topic but does the same apply if all you change are the tails thats all you would be resposible for and what tests are required is it minor works or full cert for all circuits.


Thanks

Chris
 
Good Q Chris,

I think if you are just replacing the existing tails, then a MWC would suffice.
 
Good Q Chris,

I think if you are just replacing the existing tails, then a MWC would suffice.
hi Jason S
very useful post as this is what i am going to do as my first job my brother has two CCUs one split load one wylex fuseboard and it was done by a so called electrician. the new ccu is split load half protected half not. i either want to swap the circuits from fuseboard to new CCU but will have to install RCBOs on non protected side.I also notices that the so called electrician had upgraded gas bond but not the water which is only 6mm on a P.M.E system and looks as though the insulation has been melting so not good.or i will install a completley new CCU to the regs and install 10mm to the water.The main cut out fuse has been taken out as there is no seals. I will have to notify LABC as i am only just setting up and not registered yet with governing body as i am going to use this as my major install for registration is it ok for me to pull main fuse to accomplish this i know supplier should but as the seals are missing anyway would i get away with this as far as building control go sorry for taking up the space but new to all this
 
perform an IR test between the earth an neutral bar (ensure the main earthing conductor has been disconnected)

this is likely to be done so that when you install RCD's or RCBO's with your new CU then your not likely to get any nasty susrprises with the RCD's tripping all the time due to a previous issue that is irrelelevant to your new CU change
 
Testing N-E IS a quick, basic test that does not require any disconnection.

This will at lease ensure there are no n-e faults, but will not confirm any borrowed neutrals.

EDIT: UKSEL beat me to it. :D
 
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you will need to make sure you either disconnect the main earthing conductor, or test at the neutral bar with the main switch open (otherwise you'll pick up N-E at the transformer)
 
Jason. I dont really agree with you on all points but Arsenal are on tele soon so I must fly. But in general youre right. I missed out the bleeding obvious because it is just that. But it was good of you to spend the time spelling it out! Cheers!!
 
you will need to make sure you either disconnect the main earthing conductor, or test at the neutral bar with the main switch open (otherwise you'll pick up N-E at the transformer)

You don't disconnect the earthing conductor - and I should hope the main switch is open for a dead test:)

Jason, I don't understand why your not testing L&N connected together to earth at 250v - it's only a little croc clip fly-lead from neutral bar to bus bar - or am I missing something.:)
 
Jason. I dont really agree with you on all points but Arsenal are on tele soon so I must fly. But in general youre right. I missed out the bleeding obvious because it is just that. But it was good of you to spend the time spelling it out! Cheers!!

The guide i gave was just that.... a guide.

Others may have different ways and im happy to edit with further suggestions.
 
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Hi Jason,
Wicked thread mate. Thanks for putting it up.
I have just finished a CU change and as it was my first one, did quite a bit of research on it (as you know, cos you answered about a billion of my threads!!! lol)
I found out some very handy info from 'DurhamSparky' on here, and I am sure he wont mind me passing it on, regarding changing a CU and non earthed lighting ciircuits.
The crux of it was that al lighting and switchgear needs to be changed to class 2 and a label needs to be applied to the new CU stating that the lighting circuit is not earthed and that no metal fixtures can be applied to it.
If the customer does not agree to the changes in their fixtures then a sparky is advised not to go ahead with the CU change.
He also sent me a link to an publication from the electrical safety council, that has been endorsed by NICEIC, ECAetc, outllining the specific requirements

And here it is.....

http://elecsa.co.uk/downloads/public/Reconnecting%20Lighting%20Circuits%20with%20no%20Protective%20Conductor_ESC.pdf

Hope that helps.
 
great topic,thanks jason,similar topic of my own,can you replace old cartridge fuses for plug i mcbs(old wylex unit)without having to notify under part p,i work for a registered firm but will have to wait before going it alone and getting signed up with elecsa,the idea of part p might be good but my word has it not made it even more difficult for qualified sparks working on the cards who in the future set up on their own.
 
great topic,thanks jason,similar topic of my own,can you replace old cartridge fuses for plug i mcbs(old wylex unit)without having to notify under part p,i work for a registered firm but will have to wait before going it alone and getting signed up with elecsa,the idea of part p might be good but my word has it not made it even more difficult for qualified sparks working on the cards who in the future set up on their own.

Start a new thread in the relevant forum.

More chance of it being seen in there.
:)
 
Good Q Chris,

I think if you are just replacing the existing tails, then a MWC would suffice.

The Nic man did his annual inspection recently and this topic came. RCBO on a light circuit would require an EIC for that circuit, not a MWC as you are changing the characteristics of the circuit at the point of origin. Changing the main tails would require a full EIC of the installation as you are changing the Characteristics of the whole installation.

Hope this helps

Billy
 
Just a little thing I find useful when doing a CU change.

Rather than changing it all over, go to energise and you now have circuits tripping out.

What I do first (on day of upgrade, not when initially looking at job) is take along an RCBO put that in the old board and check each circuit in that before hand. Just so you don't get any unforseen surprises, that aren't picked up by your inital inspection when you first go to look at the job.

Also that way you can get any issues sorted first, rather than the other way round.... stitched myself up like this once before.... CU swap done by 11:30, nice and easy then powered up only to find lights up, lights down and ring all tripping out. A CU change and test which should have taken 5-6 hours ended up taking me 12 hours (very stressful day) !!

Hope that helps a bit... Sy
 
Thanks for the feedback Sy hints and tips are always welcome by everyone on the forum.



Chris
 
Just a little thing I find useful when doing a CU change.

Rather than changing it all over, go to energise and you now have circuits tripping out.

What I do first (on day of upgrade, not when initially looking at job) is take along an RCBO put that in the old board and check each circuit in that before hand. Just so you don't get any unforseen surprises, that aren't picked up by your inital inspection when you first go to look at the job.

Also that way you can get any issues sorted first, rather than the other way round.... stitched myself up like this once before.... CU swap done by 11:30, nice and easy then powered up only to find lights up, lights down and ring all tripping out. A CU change and test which should have taken 5-6 hours ended up taking me 12 hours (very stressful day) !!

Hope that helps a bit... Sy

Would it not be easier to do an IR test - 250V L & N connected together and tested to earth?

Seems a lot of messing about fitting a RCBO to each circuit to get the same result that a two minute test will give you - and what do you do with an old Wylex re-wirable board?
 
"and what do you do with an old wylex rewirable doard" Bin it lol
 
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Board normally goes in the bin............. unless there is a market for them on ebay !!

"Just so you don't get any unforseen surprises, that aren't picked up by your inital inspection"
I always do a quick IR when first looking at the job, but this for a secondary thing I do just in case the IR didnt pick anything up at the time? Only takes a few mins to quickly try each circuit.

Should have said this is only any good for a domestic sort of situation. Could be a real pain in **** trying to do this with 48way board !!
 
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last week i downloaded a pdf file from this site all about changing a consumer unit and your subsequent responsibilities regarding testing etc, i gave my copy to a mate and cannot for the life of me find it again. Please could someone point me in the right direction thanks
 
earth and neutral, i think its earth, then line and neutral joined together so eathe to line neutral so not to damage equipment
 
no thats not the one Lenny sorry. on your link at the very end there are 4 more examples of "best practise" pdf's. the one im looking for is the one on the right, its all about our responsibilitys and what tests we need to carry out. The link you posted is for consumer unit changes where the lighting circuits dont have a cpc.

If i remember correctly there were 2 links in the post i cannot find and the one i want was accompanied by the one you just posted for me if that helps?
 
no thats not the one Lenny sorry. on your link at the very end there are 4 more examples of "best practise" pdf's. the one im looking for is the one on the right, its all about our responsibilitys and what tests we need to carry out. The link you posted is for consumer unit changes where the lighting circuits dont have a cpc.

If i remember correctly there were 2 links in the post i cannot find and the one i want was accompanied by the one you just posted for me if that helps?

Still not 100% sure which one you want, but following this link will take you to a page where they can all be downloaded:

Best Practice Guides | Electrical Safety Council

Have fun ;)
 
sorry i should have posted to say i'd found it on their site.

the one i wanted was the "consumer unit changes in domestic properties"

thank you for your help though, much appreciated.
 
This is a great thread and very informative although I have 1 question. Forgive me if it has been discussed elsewhere as this is a big forum :)

I am anticipating doing several additions and alterations to an existing installation such as adding sockets and lights. The consumer unit is a 16thED MK nicely done although I am upgrading the tails and also new water bond as this looks to be absent. Condition of wiring is good overall. Being as the existing board is split with 1 RCD + one half non RCD protected do I need to upgrade the board? Or do I have to replace the board to bring it in line with current 17th ed? Guess it would be easier to do that and just issue an EIC for the whole job!

I was thinking if the client does not want to pay for a board change (as most do not) I could use RCBO's.
I know that any circuits I add that are for example, chased in less than 50mm will need to be RDC protected so can I swap circuits around i the consumer unit to achieve this?

Can anyone clarify this for me.
Many thanks
 
If the CU and existing wiring is in good condition then, any circuit you alter (that is on the non rcd side), can be protected with an RCBO.
 
would you not carry out a full test before changing the cu to highlight any existing problems with the installation.you can then make the customer aware of any additional works and costs to the job.if you go ahead without any inspection and there are any faults uncovered you should then put in right.
 
If your linking the L+N and testing them between earth, why are you only using 240v instead of 500v?

Cheers :)
 

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**CU Changes And YOU**
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