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

 

[Chector]

With reference to a post you made just 5 days ago, I can only assume this is the same property:

"I would value peoples opinions the earthing arrangement I cam across yesterday. Water and Gas main protective bonding conductors were not installed at the consumer unit, but were coned to the main earthing terminal. The MET was connected to the distributors earth and one conductor ran from the MET to the consumer unit. The resistance from the consumer unit to the gas and water were fine at 0.01 Ohms. But shouldn't the conductors be wired into the consumer unit? They all need changing anyway as they were all 6mm."

http://www.electriciansforums.co.uk...trical-forum/102345-earthing-arrangement.html

So based on this, you knew they were on the small side before you started the work, so why have you carried on and not updated them?

That's not quite the case. I discovered the problem as I was replacing the consumer unit. I think I should have checked for this problem at the time of quoting and included it in the quote. However the situation in the garage was far more dangerous, so I spent my time on that. I'll go back and sort the bonding asap. Thanks for your help

 

[123]

Correct me if I'm wrong but I was under the impression that if it was solid green you have to replace it as its not even a current colour let alone size.

So you rewire the red and black also? :|

 

[SteveH40]

Would be great to live in a perfect world and look what happened in the 16th edition regs , surprised we didn't end up bonding bloody door handle and hinges! 18th edition will probably say earthing is a myth, go back to 2 core twisted cables and use the pendant as a socket for your iron lol

 

[Dave OCD]

I agree it would be good practice to replace it - most definitely the main earthing conductor, but long runs that test out fine and would cost a lot in time and money to replace- maybe just mark with green/yellow where accessible and visible, after all what else could a green single core be ?

 

[uksparks]

I don't know about you but it doesn't sound right sleaving solid green with green and yellow, that's like over sleaving black and red...

 

[Dave OCD]

Well what do you do with a three core and CPC then to identify switched lives or even neutrals properly ?:smile5:

 

[uksparks]

We are not talking about that, we are talking about over sleaving a conductor that's against regulation.

 

[Dave OCD]

I give up.

 

[uksparks]

But isn't that talking about NEW works ?

BS7671 is to be used for ALL works new or old.

Petsonally id say that if you are changing the CU and testing and reconnecting and energising circuits, you are knowingly reconnecting and using a green conductor. I know ither parts of the installation may have green, but you are not physically touching any of that, that's all hidden.

i may be totally wrong but I won't reconnect a solid green conductor.

 

[GB.Kayak]

We are not talking about that, we are talking about over sleaving a conductor that's against regulation.

... against regulation due the colour of its insulation ... BS 7671 is not retrospective so unless the conductor is not up to the job in terms of its function then it's replacement is not an issue of necessity!

 

[uksparks]

Every time I change a cu I update it, maybe it's just me, but if I went round changing cu's and left a 6mm green conductor in on the bonding every time id feel I'm doing something wrong.

 

[Dcf]

Every time I change a cu I update it, maybe it's just me, but if I went round changing cu's and left a 6mm green conductor in on the bonding every time id feel I'm doing something wrong.

What's the difference resistance wise over a bit of 6mm or 10mm Earth wire over the average distance of 10-15m in a house for the bond to the water or gas?
ill tell you
about the square root of hee haw.
by all means update the main earth to 16mm
but as for ripping out a decent bond to the water just cos its green I think it's work that's not needed
an electrician that does not know that a 6mm green to a water pipe is a bond is not much of a spark in my eyes

 

[uksparks]

an electrician that does not know that a 6mm green to a water pipe is a bond is not much of a spark in my eyes

I know it's the sodding bonding, I'm not suggesting I don't, I just think it should be updated.

 

[shanky887614]

I know it's the sodding bonding, I'm not suggesting I don't, I just think it should be updated.

why? its safe for continude service so no issue.

if i hadnt left my gn3 at the test center i would check (jtl center, aston expressway)

 

[Dcf]

Why should it be updated?
read the first bit of my post
the difference between a bit of 6mm and 10mm over the average distance in a house/flat is negligible so why rip it out because the colour doesn't suit you?

 

[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.