10ml or 6ml main bonding conductors

[smoggy]

Again cheers for advice
Can we get a member who is good with the regs?
As I do work for the local authority and when you go into a job they want the bare minim to keep installation safe keep the cost down

TapouT

You don't have to change bonding, code 4 is ok, but like has been said don't risk getting bad mouthed, just change it to 10mm, make the cost up elsewhere.

 

[jaldred]

Still think you're best checking with your registered body, NICEIC, ELECSA or whoever. The regs are pretty clear on minimum requirements but i do concede that they aren't retrospective and there are 'advisory' codes given on some other documentation i've seen (it's the regs they'll hold up in court though).
I have mates who have had to go back to properties to upgrade the bonding where there has only been 6mm, admittedly it was before the advent of the 17th edition, maybe the new regs have changed requirements?
Does anyone know if there is a reg in there giving this leeway?

 

[smoggy]

Still think you're best checking with your registered body, NICEIC, ELECSA or whoever. The regs are pretty clear on minimum requirements but i do concede that they aren't retrospective and there are 'advisory' codes given on some other documentation i've seen (it's the regs they'll hold up in court though).
I have mates who have had to go back to properties to upgrade the bonding where there has only been 6mm, admittedly it was before the advent of the 17th edition, maybe the new regs have changed requirements?
Does anyone know if there is a reg in there giving this leeway?

Correct me if i am wrong, what is basically being said here is everytime you do a job no matter how small you have to upgrade bonding if not current regs.?

 

[coxy]

Hi I would say if the main fuse in the cut out is 100 A should be 25mm tails & 16 mm earth if 60 Amp 16.mm tails ok.If tt 6mm earth ok if tn 10 mm earth.

 

[heathelect]

As a matter of course i always change mains tails to 25mm & 16mm earth, with 10mm to gas and water etc, i know other other sizes are ok for different installations, but you dont always know what the main incomer fuse size is, so i always go for the max, regards dave

 

[coxy]

Hi Sorry read the post wrong,I would always install 10mm main bonding whatever supply.

 

[saveloy]

FWIW. On surveying a potential job I ALWAYS check to see if there is the correct bonding (10mm) in place before giving an estimate and then advise on an upgrade if required. In most cases it is no big job to upgrade anyway. I just feel that it is good practice to make sure that the whole installation meets current regs when I have finished my work.

 

[laney06]

I spoke to the niceic on this very subject as i had the same issue with one of the jobs i was using for my assesment.
Basically, if tns or tt you can use the adibiatic equation to prove what size conductor you can use for your bonding ( i squared t over k, square rooted). If tncs (pme) then you refer to table 54g. (could be table 54h, i forget!) which states in a round about way you must have 16mm and 10mm bonding.
The nic position on this is thus: you MUST make sure the bonding is up to CURRENT regs BEFORE you commence work.
Therefore an installation cert cannot contain any 'codes' as you should have done this work as part of your job.
Hence me quickly selecting a new job for my assesment!!

Hope this helps.

 

[jaldred]

That's how i've experienced this subject too Laney.
It's all about the combined neutral/earth at the supply with a TNC-S. The supply authority worry that they may lose the earth somewhere down the line and that should there be any stray currents the path of least resistance could be the Final Circuit CPC's. By have 'oversized' Main Protective conductors the stray currents should exit down those instead of the casing of your kettle.

 

[TPES]

FWIW. On surveying a potential job I ALWAYS check to see if there is the correct bonding (10mm) in place before giving an estimate and then advise on an upgrade if required.

What do you do if you advise them of the upgrade to gas and water supplys and they dont want to pay for you to do it.

Do you leave the 6mm bonding in place and continue with your work, just adding a note on the cert you recommend a 10mm upgrade?

Or tell them before you start that the bonding HAS to be upgraded before you will carry out ANY alterations or additions?

 

[saveloy]

What do you do if you advise them of the upgrade to gas and water supplys and they dont want to pay for you to do it.

Do you leave the 6mm bonding in place and continue with your work, just adding a note on the cert you recommend a 10mm upgrade?

Or tell them before you start that the bonding HAS to be upgraded before you will carry out ANY alterations or additions?

TBH I have never had a customer who won't pay to have the main bonding done. And if I ever do get someone who doesn't want to pay to have work done properly then I don't lose sleep over it. I give them a quote to do the work properly, they take it or leave it. Anyone who wants to skimp on electrical work in their house probably isn't worth working for anyway. At the end of the day it's my name on the certs and my neck on the line, so I won't drop my stantards or do a half####d job just to earn a few extra quid.

 

[ezzzekiel]

I spoke to the niceic on this very subject as i had the same issue with one of the jobs i was using for my assesment.
Basically, if tns or tt you can use the adibiatic equation to prove what size conductor you can use for your bonding

The adiabitic equation is Not used to calculate the size of Main Bonding conductor 543.1.1


as an afternote, Napit allow min 6mm on tns if permission not given to upgrade and note on eic, pme rules apply