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Hi. Could someone please clarify bonding requirements for me please. I know requirements are to have a seperate 10mm earth bond conductor for water and gas or that these can be in one cable if looped between each other. I have been working in a couple of properties lately that are in residential blocks. The both have combi boilers installed. I have noticed that they don't have any seperate bonding to gas. Just one 10mm that goes to water. Is this in breach of current regs? Thing i dont quite understand is as far as I am aware all pipe work of combi boiler is interconnected so if the bond the water pipes is in place then in effect the water and gas pipes of boiler are also aren't they? If this isn't adequate and a dedicated gas bond needs to be provide is the any solution to situations where meter is situated outside apartments and can't find where enters property or where access in a near on impossibility. Any advice/clarification be appreciated
 
Hi. Could someone please clarify bonding requirements for me please. I know requirements are to have a seperate 10mm earth bond conductor for water and gas or that these can be in one cable if looped between each other. I have been working in a couple of properties lately that are in residential blocks. The both have combi boilers installed. I have noticed that they don't have any seperate bonding to gas. Just one 10mm that goes to water. Is this in breach of current regs? Thing i dont quite understand is as far as I am aware all pipe work of combi boiler is interconnected so if the bond the water pipes is in place then in effect the water and gas pipes of boiler are also aren't they? If this isn't adequate and a dedicated gas bond needs to be provide is the any solution to situations where meter is situated outside apartments and can't find where enters property or where access in a near on impossibility. Any advice/clarification be appreciated
Do you have a Gas metre or entry to your property?
 
Both of the properties have been working in lately have gas meters in communal areas of apartments
)hen bond to the communal area.? discuss, or within 60mm from where it (the gas pipe) enters your apartment, discuss
 
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The reasons for bonding the gas pipe as it enters come down the the possibility of a poor electrical connection between pipework, as plumbers have no need to make it electrically sound and might even replace bits with plastic for repairs/extensions/etc.

The guide notes shows a continuous wire but others have pointed out the actual regs don't specify that. Somewhere I have seen it said that a "permanent" join such as solder or crimp is also acceptable, but again no reference to the regs.

Often the say/show it at the meter, but again from the flat's point of view the extraneous conductive part is pipe coming in, if the meter is miles away then you would only bond to the incoming pipe.
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What I did in my flat (for better or worse!) where the lead water pipe and gas meter are close together under the kitchen sink was to run a length of 16mm from the MET to the water pipe and then crimped it using a 35mm M6 ring terminal (to connect to the water pipe clamp) along with another length of 16mm that was terminated with a 16mm M6 ring terminal (for the pipe clamp to the gas).

NOTE: My use of 16mm was simply due to having a reel of it handy!
 
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What I did in my flat (for better or worse!) where the lead water pipe and gas meter are close together under the kitchen sink was to run a length of 16mm from the MET to the water pipe and then crimped it using a 35mm M6 ring terminal (to connect to the water pipe clamp) along with another length of 16mm that was terminated with a 16mm M6 ring terminal (for the pipe clamp to the gas).

That is incorrect, you should have fitted a 16mm lug to each conductor.
Putting 2 conductors into a lug which is designed for a single conductor of a different size is wrong, it is not approved by the manufacturer, may not achieve the correct finished crimp profile and pressure.
 
The reasons for bonding the gas pipe as it enters come down the the possibility of a poor electrical connection between pipework, as plumbers have no need to make it electrically sound and might even replace bits with plastic for repairs/extensions/etc.

The guide notes shows a continuous wire but others have pointed out the actual regs don't specify that. Somewhere I have seen it said that a "permanent" join such as solder or crimp is also acceptable, but again no reference to the regs.

Often the say/show it at the meter, but again from the flat's point of view the extraneous conductive part is pipe coming in, if the meter is miles away then you would only bond to the incoming pipe.
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What I did in my flat (for better or worse!) where the lead water pipe and gas meter are close together under the kitchen sink was to run a length of 16mm from the MET to the water pipe and then crimped it using a 35mm M6 ring terminal (to connect to the water pipe clamp) along with another length of 16mm that was terminated with a 16mm M6 ring terminal (for the pipe clamp to the gas).

NOTE: My use of 16mm was simply due to having a reel of it handy!

Cheers PC I think in these scenarios I have no option but to find closest point can get access to pipework in property. Just to clarify there's no scenarios in 18th regs that a 6mm is adequate. Whether it's tns or tncs has to be 10mm for both gas and water?
 
Cheers PC I think in these scenarios I have no option but to find closest point can get access to pipework in property. Just to clarify there's no scenarios in 18th regs that a 6mm is adequate. Whether it's tns or tncs has to be 10mm for both gas and water?

It is required to be half the size of the earthing conductor and no less than 6mm except when PME conditions apply.

Bonding in a block of flats should be carried out at the point of entry to the building (landlords installation) and at the point of entry to each flat.
 
It is required to be half the size of the earthing conductor and no less than 6mm except when PME conditions apply.

Bonding in a block of flats should be carried out at the point of entry to the building (landlords installation) and at the point of entry to each flat.
Thanks Dave. So for TNCS supplies has to be minimum 10mm
 
That is incorrect, you should have fitted a 16mm lug to each conductor.
Putting 2 conductors into a lug which is designed for a single conductor of a different size is wrong, it is not approved by the manufacturer, may not achieve the correct finished crimp profile and pressure.
True it is not ideal, but the pipe clamp would not realistically take two 16mm crimp lugs. I did a reasonable pull-test on the crimp to make sure it was holding, and also it is not required to carry its rated current here.
 
Thanks Dave. So for TNCS supplies has to be minimum 10mm

The same rules apply for TNCS.
If PME conditions apply then it is usually a minimum size of 10mm.
TNCS is not necessarily a PME supply.
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True it is not ideal, but the pipe clamp would not realistically take two 16mm crimp lugs. I did a reasonable pull-test on the crimp to make sure it was holding, and also it is not required to carry its rated current here.

It is required to be an electrically and mechanically sound connection, which it may not be as it has been used incorrectly.
There's more to it than just a pull test, if you haven't achieved the correct crimping then the connection may well corrode and become high resistance or fail when current flows through it.

There's a lot more to a good crimped connection than just squashing bits of metal together.
 
the bonding should have been done from this location assuming one gas supply is for the building, bonding from within the flats would be optional in most of these situation if appropriate tests confirmed this..
Thanks bigspark your the only one who's ever clarified that. Is there any section in regs mentions this or links you know of that talks about scenarion more in depth. Would the testing just be testing between MET and any gas pipework can access and having reading below 0.05 and also the same between water and gas
 
the bonding should have been done from this location assuming one gas supply is for the building, bonding from within the flats would be optional in most of these situation if appropriate tests confirmed this..

Bonding for each installation is not optional, it either is, or is not, required.

Normally it is required, the fact that the pipework is bonded elsewhere makes it an extraneous part to the individual flats installation.
 
Thanks bigspark your the only one who's ever clarified that. Is there any section in regs mentions this or links you know of that talks about scenarion more in depth. Would the testing just be testing between MET and any gas pipework can access and having reading below 0.05 and also the same between water and gas
There no requirement for the continuity of a bonding conductor to be at or below 0.05 ohms.
The reading should reflect the length of the conductor serving the extraneous part, an engineering judgment should be made if the lengths are unknown, that the adequacy of the reading is acceptable.
 
Bonding for each installation is not optional, it either is, or is not, required.

Normally it is required, the fact that the pipework is bonded elsewhere makes it an extraneous part to the individual flats installation.

if there is only one MET by (DNO) and all appropriate main bonding is done to services that are coming into the building to the that MET why would they need supp bond withing the flat?

when i say optional, imo if the OP or others did bond in flat when it wasnt required i would be pendantic about that.
 
if there is only one MET by (DNO) and all appropriate main bonding is done to services that are coming into the building to the that MET why would they need supp bond withing the flat?

when i say optional, imo if the OP or others did bond in flat when it wasnt required i would be pendantic about that.
Usually you have a BNO for blocks of flats, each flat is a separate installation with individual metering and has their own MET. Bonding should be carried out in each individual flat if applicable.
 
if there is only one MET by (DNO) and all appropriate main bonding is done to services that are coming into the building to the that MET why would they need supp bond withing the flat?

when i say optional, imo if the OP or others did bond in flat when it wasnt required i would be pendantic about that.

Because each individual flat has its own installation, and that installation should have its own main bonding to create its own equipotential zone.
 

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