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!!
 
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**CU Changes And YOU**
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