IET
Decrease font size
Increase font size
Topic Title: Inspection & Testing
Topic Summary: Certification of electrical work
Created On: 18 September 2013 09:38 AM
Status: Read Only
Linear : Threading : Single : Branch
1 2 3 Next Last unread
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 18 September 2013 09:38 AM
User is offline View Users Profile Print this message



mazzy2000

Posts: 35
Joined: 25 June 2013

I know this topic has been discussed previously, but I am trying to gauge opinion a bit further.

My team of electricians recently carried out a distribution board replacement feeding circuits at a small railway station and in their opinion, it does not require an electrical installation certificate. My interpretation of the regulations is that this work should have been certified in accordance with 610.6 as it is an alteration in accordance with 610.4.

There are two types of certificate, but the notes on the minor works cert preclude it from being used for DB changes; therefore, an electrical installation certificate must be issued together with a full schedule of inspections and tests. This would include relevant tests/inspections on all the final circuits, even though they have only been disturbed at the distribution board.

Their argument is that there is already a valid periodic report for the board and that the board is being changed from a 30 year old Ottermill quicklag style to a modern Schneider board with type B/C circuit breakers; therefore, it is safer.

Another agrument for issuing the certificate would be for recording the differences between the two installations, even though they have likely been improved e.g. main switch characteristics, different circuit breaker characteristics (5A to 6A, 30A to 32A etc.). Also, this cert is signed off to indicate that the new installation has been designed, constructed and inspected/tested in accordance with 7671.

As a compromise, they have agreed to carry out protective conductor continuity and earth fault loop impedance tests as a minimum in accordance with 1.4 of guidance note 3. It is reasonable to assume that conductor details and insulation resistance etc. are unchanged as the circuits have not been altered. These would be re-evaluated at the next periodic inspection/test for the entire installation (which would stay at the same schedule as it was before the board was changed e.g. last done in 2011, net due in 2016 even though one of the DBs was changed and tested/inspected in 2013.

Is this considered a reasonable approach to DB replacements?
 18 September 2013 09:56 AM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

An EIC definitely should be issued. As a minimum it needs to cover just the work done, so not necessarily downstream parts that are undisturbed and unaffected by the change. As insulation faults often occur at cable terminations I can see no logic to omitting an insulation test - without that it can't be shown that the re-working of the final circuit conductors hasn't introduced a few fault.
- Andy.
 18 September 2013 09:58 AM
User is offline View Users Profile Print this message



John Peckham

Posts: 9097
Joined: 23 April 2005

Mazzy

Welcome to the forum.

Your contractors are talking bo***cks. The job requires an electrical installation certificate to be issued.Don't pay them until you get this. If they refuse then report them to the regulating body if they are a member of one.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 18 September 2013 10:10 AM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

It's not that difficult as long as you grasp the concept that relevant information is contained within more than one document.

You need an EIC for the DB change. You need a schedule for that DB change that refers to the new protective devices. The existing PIR is then cross refeernced with that schedule.

So for example - if you've changed the MCB in Way 1 L1 then that is recorded on the EIC DB schedule. If you want to know what Circuit Way 1 L1 is/does, refer to the PIR which then also contains data on IR, number of points served etc

Simples

Your in charge, tell the operatives what you want - it's not a debate with them

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 18 September 2013 11:30 AM
User is offline View Users Profile Print this message



daveparry1

Posts: 8020
Joined: 04 July 2007

Never heard such rubbish, of course it needs an EIC!

Dave.
 18 September 2013 12:11 PM
User is offline View Users Profile Print this message



MrP

Posts: 968
Joined: 24 March 2006

Mazzy welcome to the forum
One would question the competence of your contractor if their understanding of 7671 on compliance is in question therefore how can the integrity of the work completed be assured
Good luck buddy
I won't pay them to many bozoes out there

MrP
 18 September 2013 03:31 PM
User is offline View Users Profile Print this message



alanblaby

Posts: 868
Joined: 09 March 2012

Originally posted by: mazzy2000

Their argument is that there is already a valid periodic report for the board and that the board is being changed from a 30 year old Ottermill quicklag style to a modern Schneider board with type B/C circuit breakers; therefore, it is safer.


Change a DB, then no certfication? What planet are you on?

The characterisitics of all the circuits affected have changed, so they all should be tested before energising them.
 18 September 2013 03:51 PM
User is offline View Users Profile Print this message



rocknroll

Posts: 9677
Joined: 03 October 2005

Their argument is that there is already a valid periodic report for the board and that the board is being changed from a 30 year old Ottermill quicklag style to a modern Schneider board with type B/C circuit breakers; therefore, it is safer.


There is actually a lot of logic in that statement, you dont actually test the board but the circuits to the board and if on the last test they were within the bounds of Zs, IR etc then what is the problem, changing the board is not changing the parameters of the circuits but fitting a comparable unit that is in all extent better because it is more up to date using circuit breakers.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 18 September 2013 04:19 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

more up to date using circuit breakers.

It depends on what's replacing what. Change from a 5A cartridge fuse to a 6A C type MCB and the max permitted Zs might change from 8.4 Ohms to 3.09 Ohms (for 0.4s disconnection time). Changing from a 5A type 1 to a 6A type B moves from 9.27 to 7.42.

I don't think there are any grounds for a blanket 'if it's newer it must be better under all circumstances' belief, especially somewhere like a railway station where you might be looking at unusually long circuit lengths.

- Andy.
 18 September 2013 04:25 PM
User is offline View Users Profile Print this message



Parsley

Posts: 1383
Joined: 04 November 2004

Originally posted by: rocknroll

Their argument is that there is already a valid periodic report for the board and that the board is being changed from a 30 year old Ottermill quicklag style to a modern Schneider board with type B/C circuit breakers; therefore, it is safer.




There is actually a lot of logic in that statement, you dont actually test the board but the circuits to the board and if on the last test they were within the bounds of Zs, IR etc then what is the problem, changing the board is not changing the parameters of the circuits but fitting a comparable unit that is in all extent better because it is more up to date using circuit breakers.



regards


Did the contractor who replaced the DB carry out the PIR in 2011?
Was it a driveby or did he jump of the train at each station along the route and get back on the next train when it arrived 15 mins later? what were the limitations?

If it's now protected by 30ma RCD protection then why botheranyway?

Regards
 18 September 2013 04:26 PM
User is offline View Users Profile Print this message



leckie

Posts: 4705
Joined: 21 November 2008

So as OMS say then, issue the EIC recording the new CPD's, etc, fitted and record the test results from the previous PIR/EICR. if I was going to use the test results from another contractors certificate I would be stating that on the EIC.

Only problem is that in my experience a large percentage of PIR test results are created by someone's imagination so I think I would minimally want to do so sample tests and double check the limitations, etc on the PIR.
 18 September 2013 05:34 PM
User is offline View Users Profile Print this message



OMS

Posts: 22864
Joined: 23 March 2004

You can imagine what you like about the previous PIR, the fact remains that it exists, it provides all the relevant parameters for the affected circuits excepting CPD characteristics.

There is no problem providing an EIC for the board change and refering to the relevant, valid and current PIR.

Let me ask you the question - If I give you an order to change the primary distribution switchboard in your local general hospital would you then be spending the next 3 months busily retesting every circuit in the hospital - because if you are planning that I can get you guys absolutely loads of work

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 18 September 2013 09:58 PM
User is offline View Users Profile Print this message



Zs

Posts: 3877
Joined: 20 July 2006

Originally posted by: OMS

Let me ask you the question - If I give you an order to change the primary distribution switchboard in your local general hospital would you then be spending the next 3 months busily retesting every circuit in the hospital - because if you are planning that I can get you guys absolutely loads of work


OMS


Fantastic, because yes, I would. One by one. Unless my client elected to specifically exclude final circuit testing or elected that I copy test results across to the new forms and took the risk from me in writing.

When do I start?
 18 September 2013 10:19 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 17795
Joined: 13 August 2003

record the test results from the previous PIR/EICR

I'd suggest that some new tests would need to be done to prove the new work is correct - i.e. continuity, polarity, insulation test - as these could have been undermined by errors in the new work. For continuity/polariy that might need a wander lead to the 1st accessory on each circuit. What the previous PIR/EICR can give you are the circuit characteristics beyond (downstream) of the point of change - i.e. max R1+R2, which provided the connections have been soundly and correctly reinstated (as proved by the continuity/polarity tests) and the circuits neither shortened or extended then there's no need to find the end of each final circuits and verify R1+R2 or Zs from there.

So in a test results recorded should be from fresh tests, but unchanged circuit characteristics (i.e. things that could have come from a design rather than necessarily a test) can come from previous documentation.

- Andy.
 18 September 2013 10:29 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 9097
Joined: 23 April 2005

OMS


"You can imagine what you like about the previous PIR, the fact remains that it exists, it provides all the relevant parameters for the affected circuits excepting CPD characteristics."

You would need a huge leap of faith and trust to accept that as a fact unless you measured and recorded those results yourself because as we know most PIRs/EICRs are fabrications produced by half wits.

As for changing a primary distribution board in a large hospital no you would not test all the final circuits from the sub boards but you would test the distribution circuits to those sub boards from the primary board. That question is answered in the ESC Guidance in question Q2.15.

Also you would want to inspect and test the installation after the board has been changed because the best of people make mistakes. I tested an installation recently after a board change and found a reverse polarity on a circuit where the cable terminations had been reveres ed on an RCBO. The very competent and diligent electrician was mortified when I pointed out the error.

A colleague of mine did a periodic on a school 5 years after all the DBs had been changed by an NICEIC Approved contractor. He found most circuits were unearthed because the original circuits relied on the conduits as a CPC which were connected to the old DBs. The conduits had been cut back and dropped in to a plastic trunking above each DB hence unearthed circuits. Also every board was full of Type D breakers. There was an EIC for the installation of the boards completed by the contractor with satisfactory EFLI results for each circuit.

I think we all agree an EIC is needed? I don't think I would agree 1. To use other people's test results. and 2. Even if I had carried out a PIR I would sign off an EIC without ANY further testing.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 18 September 2013 10:50 PM
User is offline View Users Profile Print this message



Legh

Posts: 4427
Joined: 17 December 2004

Originally posted by: Zs

Originally posted by: OMS

Let me ask you the question - If I give you an order to change the primary distribution switchboard in your local general hospital would you then be spending the next 3 months busily retesting every circuit in the hospital - because if you are planning that I can get you guys absolutely loads of work

OMS


Fantastic, because yes, I would. One by one. Unless my client elected to specifically exclude final circuit testing or elected that I copy test results across to the new forms and took the risk from me in writing.

When do I start?


Ditto... I fancy a 6 month jaunt in a hospital honing my skills at a reasonable salary, of course....

Legh

-------------------------

http://www.leghrichardson.co.uk

de-avatared
 19 September 2013 06:33 AM
User is offline View Users Profile Print this message



normcall

Posts: 8550
Joined: 15 January 2005

Doctors and nurses come to mind!

-------------------------
Norman
 19 September 2013 07:07 AM
User is offline View Users Profile Print this message



davezawadi

Posts: 4259
Joined: 26 June 2002

Mazzy
The question to ask here is why they do not want to issue a certificate? Unfortunately the usual answer is somewhere between "can't be bothered" and "I'm not taking responsibility for my work". Both of these show a dreadful lack of professionalism and competence.

It is likely that they do not want to do much testing, but this is not a problem really, they are lazy and want to knock off early!
My method would be to verify a couple of the circuits on the PIR, to see if it is genuine (sockets as this is easy). If all is well the it is probably OK to rely on the PIR circuit numbers; If not then you do the lot! As I have said before, I would test every point with a loop tester, and each circuit when disconnected for insulation to earth. Circuit R1+R2 values need to be checked and matched to the new breaker type. Fill out the form, job done. You have your EIC.

I concur with all the comments below, but this sort of thing is happening all the time. You need to make a complaint to the scheme provider, not that it will do much good I'm afraid.

-------------------------
David
BSc CEng MIET
 19 September 2013 07:32 AM
User is offline View Users Profile Print this message



leckie

Posts: 4705
Joined: 21 November 2008

I thought R1+R2 tests were only an actual requirement for initial verification?

The test is not in the list of test for EICR's in GN3 as far as I recall. I would think it would be optional and only ELI test is required even though this is not an EICR but an alteration. Or whichever way is the easier in the circumstances.
 19 September 2013 07:53 AM
User is offline View Users Profile Print this message



dickllewellyn

Posts: 1434
Joined: 19 March 2010

Personally I think the meeting of two opposite extremes will work just nicely. You have the previous PIR, so that helps to get the ball rolling. When putting the board back together, I personally feel its lazy not to make off all the earths, croc to that, and insulation test to lives and neutrals as they are terminated. These readings can be compared to those on the PIR. If they are miles out and look made up, the alarm bells start to ring and further testing can be carried out more diligently. If you are getting readings such as for example 29megohms consistent with the PIR, the clues would suggest they're not made up! Wilst terminating, if there are any rings, it seems daft for the sake of a couple minutes not to test their continuity, and again compare the resistance with the PIR. If there are any vast differences, again you know where to start looking.

With circuits insulation tested and terminated, assuming the r1r2 and Zs readings on the PIR are within parameters for new protective devices, I would personally fire up circuits one at a time, checking they are in fact what the PIR said they were, and running round a few accessories with a loop tester verifying polarity and Zs. A certificate can then be produced with a combination of results taken on site, and results gained from the PIR.

That's how I'd do it.

Now. About this hospital job?!

-------------------------
Regards
Richard (Dick)

"Insert words of wisdom and/or witty pun here"
IET » Wiring and the regulations » Inspection & Testing

1 2 3 Next Last unread
Topic Tools Topic Tools
Statistics

New here?

  • To participate in discussions, please log in and introduce yourself.

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2021 FuseTalk Inc. All rights reserved.

 
..