Bonding combi boiler gas pipes

[MickSmith5824]

From my understanding you need to run both a 10mm earth from CU to water stop clock and seperate 10mm to gas, exception being if cable is uncut can link both gas and water together. In a scenario where been asked to change consumer unit but getting to gas pipes of combi boiler is practically impossible what are options. My thinking is that if water pipes tested and proved to be bonded correctly why would it not be feasible to link out water pipes and gas pipes of combi boiler. This then brings all pipework upto to same earth potential no?

 

[Pete999]

From my understanding you need to run both a 10mm earth from CU to water stop clock and seperate 10mm to gas, exception being if cable is uncut can link both gas and water together. In a scenario where been asked to change consumer unit but getting to gas pipes of combi boiler is practically impossible what are options. My thinking is that if water pipes tested and proved to be bonded correctly why would it not be feasible to link out water pipes and gas pipes of combi boiler. This then brings all pipework upto to same earth potential no?

10mm2 main bonding conductor to the gas intake to the dwelling consumers side not at the Gas boiler, within 600mm I believe

 

[westward10]

BS7671 does not stipulate a continuous conductor. Can you verify bonds to both services.

 

[MickSmith5824]

10mm2 main bonding conductor to the gas intake to the dwelling consumers side not at the Gas boiler, within 600mm I believe

It's an old council block don't think there is any gas supply into properties, certainly not a gas cooker. If it only has a combi boiler does this mean that there is a gas supply? Confuses me to be honest my own property has no gas supply for cooking but they have run both 10mm to water and gas side pipes of combi

 

[westward10]

Combi boilers are predominantly gas however other fuels such as oil and electric can be used.

 

[pc1966]

From my understanding you need to run both a 10mm earth from CU to water stop clock and separate 10mm to gas, exception being if cable is uncut can link both gas and water together.

They suggest continuous / uncut wire but I think any form of permanent join is acceptable, such as a crimp or solder. The concern (as I understand it) are screw joints loosening with vibration or temperature cycling.

My thinking is that if water pipes tested and proved to be bonded correctly why would it not be feasible to link out water pipes and gas pipes of combi boiler. This then brings all pipework upto to same earth potential no?

Relying on conductive pipes is a dubious thing, as often if a repair or upgrade is made the plumber will replace a metal section with some push-fit plastic stuff as it is quicker/easier/cheaper (to them).

Is there any bonding present now? Can you run a cable to the nearest accessible part of the gas pipe?

 

[westward10]

BS7671 does not suggest the bonding conductor to be continuous or give methods of how it should be made continuous. Guidance Notes do indeed suggest a continuous conductor however it does not cite a Regulation to support this.

 

[pc1966]

BS7671 does not suggest the bonding conductor to be continuous or give methods of how it should be made continuous. Guidance Notes do indeed suggest a continuous conductor however it does not cite a Regulation to support this.

Agreed, I was looking at the guidance notes recently which shows this.

 

[Pete999]

It's an old council block don't think there is any gas supply into properties, certainly not a gas cooker. If it only has a combi boiler does this mean that there is a gas supply? Confuses me to be honest my own property has no gas supply for cooking but they have run both 10mm to water and gas side pipes of combi

Surely if you have a gas boiler, stands to reason you have a gas supply/meter. other wise how are you charger for the gas you use

 

[R-fur]

If you use LPG it is rare to have a meter.

 

[Pete999]

If you use LPG it is rare to have a meter.

Good point never gave it a thought.

 

[davesparks]

From my understanding you need to run both a 10mm earth from CU to water stop clock and seperate 10mm to gas, exception being if cable is uncut can link both gas and water together.

Bonding needs to be connected to all extraneous conductive parts at their point of entry to the installation. This is not necessarily limited to water and gas pipes, and not all water or gas supplies are extraneous conductive parts.
Bonding is not always 10mm, depending on the characteristics of the incoming supply or requirements of the DNO it can be bigger or smaller.
Bonding does not have to be seperate conductors to each service, nor does it have to be unbroken.

 

[radiohead]

From my understanding you need to run both a 10mm earth from CU to water stop clock and seperate 10mm to gas, exception being if cable is uncut can link both gas and water together. In a scenario where been asked to change consumer unit but getting to gas pipes of combi boiler is practically impossible what are options. My thinking is that if water pipes tested and proved to be bonded correctly why would it not be feasible to link out water pipes and gas pipes of combi boiler. This then brings all pipework upto to same earth potential no?

It may do or it may not. If there was an insulating section in the pipework or a poorly conducting joint between the point of entry and the combi then it may result in unbonded extraneous pipe between the point of entry and the combi.
The whole point of bonding an extraneous service at the point of entry is that the hazard is introduced from outside, once within a building it is unlikely to pick up an external earth potential again. By bonding at the point of entry it can reasonably be assumed that the hazard is dealt with. That's not the case if bonding takes place elsewhere.

 

[Ian1981]

Where do people prefer to bond structural steel?
There is no ‘as close to entry point’ other than towards the ground and has multiple points but are usually connected together.

 

[radiohead]

Where do people prefer to bond structural steel?
There is no ‘as close to entry point’ other than towards the ground

Usually at the most convenient place! Where there are a number of steel structures in the ground I do usually do a visual verification that various sections are bolted together and do an R2 test to a few sections after the bond is connected. Granted though in general little thought is given to bonding extraneous steelwork