Bonding gas/water yellow and blue

[mattg4321]

544. 1.2

“The main equipotential bonding connection to any gas, water or other service shall be made as near as practicable to the point of entry of that service into the premises. Where there is an insulating section or insert at that point, or there is a meter, the connection shall be made to the consumer's hard metal pipework and before any branch pipework. Where practicable the connection shall be made within 600mm of the meter outlet union or at the point of entry to the building if the meter is external”

Strongly implies that you shouldn’t bond at the meter box. However I do bond there if that’s the most practical place for it. Meter fitters hate it when I point out this regulation to them after I’ve bonded at the point of entry. Say where the pipe work comes out of a semi buried meter box and in through the wall to a cupboard housing the boiler.

A bit of common sense is all that’s needed

 

[willy fixit]

Common sense...
Muppet missed one out!

 

[charlie76]

Even with a plastic incoming water supply, if the installation is completely metallic (copper) it will almost definitely be introducing earth potential via the connection at the boiler. Where the plumber has bonded all the pipes together at the boiler as in the above picture, you can be sure all the metallic pipework will be introducing earth potential as the gas supply pipe to the boiler will be metallic and earthed at the boiler.

So unless you can confirm the pipework is not at earth potential (which it will be if it is an all metallic installation and the boiler supply is correctly earthed) then it will need bonding.

 

[Deleted member 26818]

Even with a plastic incoming water supply, if the installation is completely metallic (copper) it will almost definitely be introducing earth potential via the connection at the boiler. Where the plumber has bonded all the pipes together at the boiler as in the above picture, you can be sure all the metallic pipework will be introducing earth potential as the gas supply pipe to the boiler will be metallic and earthed at the boiler.

So unless you can confirm the pipework is not at earth potential (which it will be if it is an all metallic installation and the boiler supply is correctly earthed) then it will need bonding.

If the gas supply is metallic and bonded, and the water supply is plastic but the internal metallic water pipes are cross bonded with the metallic gas pipe, then it will all be at the same potential

 

[Deleted member 26818]

View attachment 40776 Common sense...
Muppet missed one out!

Waste of time cross bonding that lot, they’re all joined together by that bracket.

 

[Wilko]

Waste of time cross bonding that lot, they’re all joined together by that bracket.

Makes me laugh

 

[Pete999]

Makes me laugh

Taught at a Electrical Trainee course no doubt.

 

[charlie76]

If the gas supply is metallic and bonded, and the water supply is plastic but the internal metallic water pipes are cross bonded with the metallic gas pipe, then it will all be at the same potential

Agreed. But.... not relevant. If that was acceptable then you could say let’s only bond the gas even if the water is on a metallic supply pipe as it’s all at the same potential.

I’m only interpreting the regs.

 

[Midwest]

If it’s extraneous, then it would be main bonding.
Supplementary bonding is for special locations and where Zs of a circuit is too high.

Seems strange we are using a test for verifying the effectiveness of supplementary bonding, to establish if something needs to have main protective bonding conductor?

 

[Ian1981]

It’s not a test to verify supplementary bonding at all.
As bs 7671 states where doubt exists about the effectiveness of supplementary bonding conductors then the formula 50/Idelta N can be used in the case of an rcd or 50/Ia , if No rcd ,can be used to determine the effectiveness of the supplementary bonding to pipework

 

[Ian1981]

Agreed. But.... not relevant. If that was acceptable then you could say let’s only bond the gas even if the water is on a metallic supply pipe as it’s all at the same potential.

I’m only interpreting the regs.

no you couldn’t say that because the pipework could be altered or even disconnected which is why we provide bonding as close to the intake position as possible and before any branches or tee sections

 

[Midwest]

It’s not a test to verify supplementary bonding at all.
As bs 7671 states where doubt exists about the effectiveness of supplementary bonding conductors then the formula 50/Idelta N can be used in the case of an rcd or 50/Ia , if No rcd ,can be used to determine the effectiveness of the supplementary bonding to pipework

I don't how to respond to your post, isn't your first & second paragraph the same statement?

 

[Ian1981]

I’m saying testing a piece of metal to see if it’s an extraneous conductive part isn’t the same test to verify supplementary bonding conductors where doubt exists over there effectiveness.
I thought it was quite clear really.

 

[Midwest]

I’m saying testing a piece of metal to see if it’s an extraneous conductive part isn’t the same test to verify supplementary bonding conductors where doubt exists over there effectiveness.
I thought it was quite clear really.

I'm not trying to be confrontational, just trying to understand. I thought there was only one testing procedure, aka 415.2.2 and or Chris Kitcher video explanation.

 

[Ian1981]

I'm not trying to be confrontational, just trying to understand. I thought there was only one testing procedure, aka 415.2.2 and or Chris Kitcher video explanation.

No confrontation by me was meant it’s just the way the txt has come out I think.
I know the testing of extraneous parts comes from Gn8 and the 10mA “yeah I felt that “ approach.

 

[Midwest]

No confrontation by me was meant it’s just the way the txt has come out I think.
I know the testing of extraneous parts comes from Gn8 and the 10mA “yeah I felt that “ approach.

I'll have a read of GN8 & 3. Only asking as I come across a lot of existing PME installs, with existing bonding to plastic copper combo's in 6mm (16mm tails).

Edit; think I asked some advice from Elecsa Tech', see if I can dig up their response. I know the stance now with a metal service, is it must be upgraded to 10mm, whatever. Which is a nonsense, when doing some minor work!

 

[Deleted member 26818]

You don’t have to upgrade, unless there is evidence that the existing bonding is under stress.

 

[Ian1981]

I'll have a read of GN8 & 3. Only asking as I come across a lot of existing PME installs, with existing bonding to plastic copper combo's in 6mm (16mm tails).

Edit; think I asked some advice from Elecsa Tech', see if I can dig up their response. I know the stance now with a metal service, is it must be upgraded to 10mm, whatever. Which is a nonsense, when doing some minor work!

Well this is from the Electrical safety council website.
It’s down to the installer I guess and his interpretation of the requirements of bs 7671
Q1.67 When carrying out electrical work on an installation forming part of a TN-C-S system, is it necessary to upgrade existing 6 mm² protective equipotential bonding to 10 mm²?
Not necessarily. If the existing 6 mm² bonding connects all the extraneous-conductive-parts to the main earthing terminal, has been in place for a significant time and shows no signs of thermal damage, then it may not require to be upgraded.

Regulation number(s)

• 132.16
  
• 544.1.1

 

[Midwest]

There has been - Certsure wise - a change to that particular guidance. As its taken me about ten mins to post these few lines, I'll post tomorrow, when its less busy!

 

[Ian1981]

There has been - Certsure wise - a change to that particular guidance. As its taken me about ten mins to post these few lines, I'll post tomorrow, when its less busy!

Well I can’t see how say you move a light switch from one wall to another and you complete a minor works certificate PME earthing arrangement.
If the main protective bonding is in 6mm and has been there say all the installations life maybe 30 years, then to say you have to upgrade to 10mm which could be a pig of a job is ridiculous in my opinion