Major works notification

[Chector]

Hi, I've changed a consumer unit for a customer but noticed the earth and bonding conductors were undersized at 6mm csa. Do I put this down as a departure from 7671 or not issue to cert until the problem is rectified?

Thanks

Chris

 

[uksparks]

If it's TNCS it would need to be 10mm

 

[tigerpaul]

if the bond is adequate, and tests fine and is connected correctly. Then why not just list it in the departures from BS7671 section of the test sheet.
i wouldn't have thought ripping it out and replacing green with green & yellow, is entirely necessary.

 

[shanky887614]

If it's TNCS it would need to be 10mm

the regs are not retrospective so no.

would you force someone to upgrade the tails to there old wylex rewireable and change to a new bonding cable just to replace a cracked socket?

 

[Dcf]

If it's TNCS it would need to be 10mm

In a new installation yes you are correct.
in a job with a green 6mm Earth bond it's probably been done to the 14th edition and as the regs aren't retrospective it's ok if you are changing a board over in my eyes.

 

[uksparks]

Maybe I just like green and yellow and prefere to be modern and stylish and do away with green.

to be fair if it's solid green, chances are the rest of the installation is crappy and probably needs a rewire as its donkeys years old.

 

[tigerpaul]

Hold on, everyone has just missed the bleeding obvious.
Wouldn't a nice little sticker detailing "colours to to versions of BS7671" cover this little issue ?

 

[SteveH40]

Having followed and read through all the posts in this thread it's clear to see that we all have our own opinions on how to interpret the regulations and what is reasonably practicable to achieve. Ultimately as an electrician it's down to you to make the judgement call based on your experience and technical knowledge of the installation. If tests provide satisfactory results and you mark the certificate accordingly that the bonding would be required to be upgraded to 10mm to comply with 17th edition amd3 regulations I see no harm in leaving it as is in the short term. Unfortunately it all also comes back to what the client will allow you to do and what costs will be involved, before anyone starts shouting about costs and safety, as the financial controller at our firm once stated to me, every decision is a financial decision....................

List it as a non-compliance / upgrade required / recommended. Issue and give costs to rectify....... It's then down to the client to decide the next step.

 

[alanl]

It's quite amazing to see so many 'views', on such a simple subject.
Old installation. Possibly undersized earthing conductor, possibly undersized bonding.
So, we get our Regs book out, and see what it says about Earthing Conductor size. So we look at 543.1.1.
Where we see we can either used the easy to read, idiot proof table for the size, or, we do a test measurement, then calculate the required size of conductor.
In 95%+ of installs, the size given in the table will be too big, but that is why it is there, it is to make it idiot proof, and errs on the side of safety.
So we have a 6mm bonding. OK, get GN8 out, and read about it in there (as well as more info on the earthing conductor).
Firstly colour - you can still use green if it is identified correctly .514.3.2
Size - GN8 , Page 58 on (last years GN8, not the new one). Identify if the cable will meet the requirements there, which in 99.9% of installs, it will.

So, 5 minutes of testing, calculations , inspection, and sleeving of green cable, then you are likely to not have to upgrade anything.
That'll save the Installer 1 hour+ of work, the householder a larger bill, and fully comply with the Regulations.

Short version of above - buy GN8, and read it thoroughly.

 

[DPG]

Personally I wouldn't leave a solid green conductor in place on the bonding, ok I know it may be in the back boxes etc on the CPC and the like. I don't know, but I wouldn't be too happy leaving it.

So on a CU change where the install has green bonding cables, you would rip out the entire lengths of 10mm green bonding cable and replace them with 10mm green/yellow bonding cables? Am I missing something here? Daz

 

[nowaypedro]

The response given by alanl is bang on.