6mm water bonding on PME

[TheCodboy]

Hi all, I imagine that this has been asked a few times, but here goes. A customer who is selling their house has been on looking to change the consumer unit. Getting to the gas isnt a problem but the water is impossible without desctruction of some sort. Concrete floors, and the stopcock is on the other side of the house to the CU, and its also on the adjoining side of next door. Now as i would class this as alteration, i think that reg 132.16 covers me not to touch it, if there are no signs of deteriation and i have a continuity reading. What do you guys say?

 

[TheCodboy]

Estate agents !

Im not bothered who says it if im getting the work!!

 

[Midwest]

if there's no sign of thermal damage, you can leave as is, but add a comment on cert. you may find that the water is bonded to the gas at the boiler anyway.

Tin hat on here, but just before I finished, I recall some guidance coming out from my then Scheme, that the ole sign of thermal damage, could not be used anymore. It was either the correct size or it’s not.

 

[Ian1981]

Tin hat on here, but just before I finished, I recall some guidance coming out from my then Scheme, that the ole sign of thermal damage, could not be used anymore. It was either the correct size or it’s not.

That guidance is still issued by the electrical Safety First BPG’s Currently updated to incorporate the 18th edition, so I’d say it’s still relevant.
Much like a plastic CU doesn’t mean the installation is dangerous, an undersized bonding conductor doesn’t necessarily mean that it’s dangerous either.

 

[radiohead]

Tin hat on here, but just before I finished, I recall some guidance coming out from my then Scheme, that the ole sign of thermal damage, could not be used anymore. It was either the correct size or it’s not.

Correct. Guidance from the NICEIC to it's members now is undersized main bonding cannot be left if alterations and additions are taking place.
To the OP. I had a similar problem recently, I got a plumber to install a short plastic section just beyond the stopcock. Was a lot cheaper and less disruptive than getting a 10mm to it on that job. Might be an option for yours as well and covers your ---.

 

[Strima]

My house is a very similar build and layout to the OPs. Luckily I had extensive kitchen works done a couple of years ago so I managed to pull in a 10mm bond but it still took me a couple of hours of lifting carpets and cutting chipboard flooring to get the cable in. Annoyingly a few months later I would not have needed a bond as the incomer is plastic and there's no earth potential...

For a simple board swap this scenario would add a lot to the price of a job and most customers would refuse to have the work done purely for the disruption and mess.

Potentially one method would be to convert the earthing arrangement to TT but then this has it's own inherent issues.

What's to stop some unscrupulous individuals from splicing 10mm onto the 6mm just out of sight to appear to comply with 544????

 

[Andy78]

Correct. Guidance from the NICEIC to it's members now is undersized main bonding cannot be left if alterations and additions are taking place.
To the OP. I had a similar problem recently, I got a plumber to install a short plastic section just beyond the stopcock. Was a lot cheaper and less disruptive than getting a 10mm to it on that job. Might be an option for yours as well and covers your ---.

That's not the case going by the guidance endorsed by the IET, and they write the regs. I'll stick with that.
6mm is deemed adequate in any situation.

 

[sinewove]

If the water main is PVC, it doesnt need bonding!

PS It always amazes me this, why do people who are selling a property think that they have to change the consumer unit?

Could it be because the buyer might say it needs rewiring and knock a load off the price?

 

[TheCodboy]

My house is a very similar build and layout to the OPs. Luckily I had extensive kitchen works done a couple of years ago so I managed to pull in a 10mm bond but it still took me a couple of hours of lifting carpets and cutting chipboard flooring to get the cable in. Annoyingly a few months later I would not have needed a bond as the incomer is plastic and there's no earth potential...

For a simple board swap this scenario would add a lot to the price of a job and most customers would refuse to have the work done purely for the disruption and mess.

Potentially one method would be to convert the earthing arrangement to TT but then this has it's own inherent issues.

What's to stop some unscrupulous individuals from splicing 10mm onto the 6mm just out of sight to appear to comply with 544????

Im shocked at such a suggestion........

 

[radiohead]

That's not the case going by the guidance endorsed by the IET, and they write the regs. I'll stick with that.
6mm is deemed adequate in any situation.

So lets say in a non dwelling setting the minimum (based on the supply N) required copper main bonding conductor according to BS 7671 for a TNCS supply is 35mm you'd happily leave a 6mm in place as you've stated it is adequate in any situation?

 

[davesparks]

So lets say in a non dwelling setting the minimum (based on the supply N) required copper main bonding conductor according to BS 7671 for a TNCS supply is 35mm you'd happily leave a 6mm in place as you've stated it is adequate in any situation?

Where is that in BS7671?

As far as I am aware there is no distinction between dwellings and non dwellings with regards to the sizing of the main bonding.

 

[radiohead]

Where is that in BS7671?

As far as I am aware there is no distinction between dwellings and non dwellings with regards to the sizing of the main bonding.

Where did I state there was a distinction between dwellings and non dwellings in Bs7671?
I used an example of a non dwelling simply because it is highly unlikely that a 35mm bonding conductor will be required in any dwelling.

 

[Andy78]

So lets say in a non dwelling setting the minimum (based on the supply N) required copper main bonding conductor according to BS 7671 for a TNCS supply is 35mm you'd happily leave a 6mm in place as you've stated it is adequate in any situation?

This thread is about work in a domestic dwelling installation and the guidance I mentioned also deals with this situation. I was trying to keep the advice relevant.